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Full text of "Bridges, structural steel work, and mechanical engineering productions"

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BRIDGl S, 
STRUCTl RaL STHEL WORK, 



AM> 



MECHANICAL INdlNEERINd PRODUCTIONS 






SIR WILLIAM AI!ROL AND COMPANY, Ltd 

DALMARr^OCK IRON WORKS. 

GLASGOW, 



ith Descri| i o Vlan taring and Formn and Diagm 

for the Hon <»» ions, and other 

Data Infltu the D< tructural Work. 



BNOINBBRINO. 






!'ubll»»b«tj rivate Circulation by 

WIN, ill and »<l> RTRBE1 



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BRIDGES, 



STRUCTURAL STEEL WORK, 



AND 



MECHANICAL ENGINEERING PRODUCTIONS 



m 



SIR WILLIAM ARROL AND COMPANY, Ltd 

DALMARNOCK IRON WORKS, 

GLASGOW, 



With Description of their Manufacturing Works, and Formula? and Diagrams 

for the Calculation of Beams, General Specifications, and other 

Data Influencing the Design of Structural Work. 



Partly Reprinted from " ENGINEERING." 



Published for Private Circulation by 

a ,* RFnFOPn STREET, STRAND, LONDON, W.C 
"ENGINEERING," LTD., 35 and 36, BEDhOKU mkcci, 



1909 




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Preface. 



This work, mostly reprinted from •' Engineering," is illustrative of 
work undertaken by Sir William Arrol and Company, Limited, during the 
last forty yens. It incidentally records the history of the modern develop- 
ments in the Art and Science of Bridge Construction, as the undertakings 
successfully completed by the firm are not only representative of varied 
practice in bridge building, but include such historical structures as the 
Forth, Tower, and Tay Bridges. Many of the bridges described have 
been constructed from the firm's own designs. 

In the design and construction of another class of structure, that of 
Steel Framed Workshop Buildings, the firm has als. ■ taken a leading place, 
and many examples of these buildings are to he seen in the large industrial 
establishments throughout the United Kingdom and many Foreign countries. 

Another branch of engineering has been developed in the design and 
manufacture of machine tools, hydraulic riveting machines, bending presses, 
cranes and pumps, shipyard crane structures ami equipments, electric hammer- 
head cranes, and in pneumatic sinking plant for bridge foundations. Sir 
William Arm] and Company, Limited, have also taken a prominent part in the 
development of mechanical appliances for the charging and discharging 
of gas retorts, and in the mechanical handling and transport of coal 
and other materials. 

The Editor is indebted to Mr. Adam Hunter, ML Inst. C. EL, for the notes 
memoranda, and general specifications relating to the design of structural 
work which is published in the Appendix. The mathematical formula- have 
been carefully checked and extended by Mr. Robert Boyle, B.Sc, and several 
new- cases of inclined beams, eccentrically loaded columns and portals have 

been given. The specifications will be of service to Engineers in standardising 
the work in the Design and .Manufacture of Bridges, Cranes and General 
Structural Steelwork, and will ensure the best practice and workmanship. 
The data have been prepared and compiled to afford useful information to 
those interested, and references are given where fuller information may be 
obtained. 

London, Jul;/ 1909. 



*z l * 



fir 






'- 












X" 












' 









Contents. 



Examples of Structural Steel Work for the Following Fi 

John Browu and Co., Ltd., Sheffield and Clydebank ... 
William Beardmore and Co., Ltd., Dalmuii 
Vickers Sons and Maxim, Ltd., Barrow-in-Fumesa 
Shipbuilding Berth Equipmenl at Harland and Wolff, Belfasl 
Tranmere Bay Development Co., Ltd., Birkenhead 
Fairfield Shipbuilding and Engineering Co., Ltd., G-ovan 
( n\ i- Mt ry Ordnance Works, Glasgow 
Glenfield and Kennedy, Ltd., Kilmarnock . . 

Wallsend Slipway and Engineering Co., Ltd.. WaUsend-on-T 
Scotts' Shipbuilding and Engineering Co., Ltd., Greenock 
Yarrow ami Co., Ltd., London and Scotstoun 
Parsons Marine Turbine Co., Ltd., Wallsend on-Tyue... 
Babcock and WiUcojc, Ltd., Renfrew 

David R«»wan and Sony, Glasgow 
G. and J. Weir, Ltd., Cathcarl 



RMS 



IH' 



Foundations of Success: Including a History of Sir William ArrolandCo. 

I in-: Dalmarnock Works at Glasgow: A Description of the Methods of 
Manufacture and of thb Plant 

Bridge Building : 

A Retrospect 

List of Principal Bridges built by sir William Arrol and Co., Ltd 

The Forth Bridge 

The Tay Bridge . . 

The Tower Bridge 

Road Bridges over the Nile at Cairo 

Bridge over the River Wear at Sunderland 

The Scherzer Rolling Lift Bridge over the Swale 

Viaducts over the Rivera Barrow and Suir in Ireland... 

The Caledonian Bridge over the River Clyde at Glasgow 

The Ri'dheinji I >ridge over the River Tyne 

The North Bridge, Edinburgh 

Sudan Railway Bridges... 

Swing I'.rid-e tor Railway over a Canal 

The Dalginross Bridge at Comrie 

The Manchester Ship Canal Bridges ... 

Mack friars Bridge, London 

\'iadnct over the W'alnev Channel at BaiTOW-in-Furness 

Structural Steel Work ; 
The hesi^nof Workshops 
Table Enumerating Principal Workshopfi Built by the Finn 



i\\i;e 
1 

29 



59 
64 
66 

79 

87 
93 

97 
103 
108 
115 
119 
123 
126 
128 
130 
133 
136 a 
138 



139 
142 



146 
150 
158 
160 a 
161 
164 
168 
171 
172 
176 
178 
186 
188 
190 
194 




i}^m 



SsS. 



9Zi 












VI 



CONTENTS. 















ExAMPLBSoi Structure Steel Woa F w '— <"""'' * 

Stewarts and Lloyds, Ltd., Coatbridge ••■ 

Neilson, Reid and Co., Ltd. now North British Loco tiv, Co., Ltd I.Glasgow 

John Spencer and Sons, Ltd., Newburn 

Marshall, Sons and Co., Ltd., Gainsborough 

Charing Cross, City and VYesI End Electric Co. (Bow Station) 

A. Guinness, Son and Co., Ltd., Dublin 

Chimnej Stack at Guinness's Brewery 

Mechanical Engineering : 

Experience and its Application .. . 

Hydraulic Pumps 

Hydraulic < ranea 

Hydraulic Riveting-Machines ... 

Hydraulic Retort Machinery foi Gas \\ rks 

Coal-Elevating and ( Jonveying Planl ... 

Hydraulic Motors 

Hydraulic Valves and Fittings 

Hydraulic Stamping Press 

Light-Pi iwer Stamping l?ress 

Hydraulic Flanging Press 

Portable Hydraulic Jack 

Hydraulic Press for Forming Knei - and othei Stiffening Unite 

Hydraulic Angle-Cutting Machine 

150-Ton Electric Hammer Hi ided Crane al Clydebank Works 

Specification for the Structural Portion oi Heav\ Cram 

Electric Derricks for Shipbuilding Berths 

Compressed Aii Planl for Sinking Piers and Shafts ... 

Appendices : 

Formulae and Diagrams for the Calculation of Beams . 

Continuous < lirders 

Special Cases j Lnclined Cantilevers and Beams 

Moving Loads 

Influence Lines ... 

■ • ■ 

I iolumns with Eccentric I ids 

-•• ... .. ... ... 

p °rtal Bracing 

• - * ... ... ... 

Columns ... 
Eccentric Loads ... 

General Formulae for Momenl of Inertia, Radius of Gyration, etc., of Beams, si 
and Various S< i tions 

... 

Beams of Solid Cross Section 
Deflection of Framed Structures 
Redundant Frami - 

Cabined Stresses. Cr Bending and Direct Tension oi Compression 

Strength oi Km 

Weh Plates 
Buckled Plates . 



■ ■ ■ 



• • • 



• - • 



• • 



afts, 



■ . i 






■ . . 






I 

198 
- 
202 

208 



2) 

21 
23 
10 

24 

'.Ml 
•J I 7 
,0 
25 
25 I 
_. 

257 
259 
21 

270 
272 
275 



• ' 



28 I 
301 

313 
318 

:;. 

332 

340 

: I 

34 
364 

36 

JO 
371 

n 

373 



- 



I ONTBNTS. 



« - 



VII 



I or.-- 




































< JinltTs 



APPENDICES (continued) : 

l ' -i i ii_::lT f. ] Sheets 

Strength of Flat Plates 

Bearing Plates 

Ball Bearings 

Roller Bearings ... 

Bearing Pressure 

Friction Experiments 

Economical Depths of Girders ... 

Loads on I rirders in Walls 

Approximate Weights of Travelling Cranes 

Distribution of Crane Wheel Loads on Top Flanges of Gantry 

Lateral Forces on T<>|> Flanges of Gantry Girders 

Water Pressure ... 

Wind Pressure ... 

Roof Drainage 

Temperature 

Hollow Cylinders ... ... ... . . 

The Friction of Hydraulic flams 

X< itl> m]| F"Ul|<|;i1 Jong 

i !< mcrete Foundations 
Timber Piles 

Resistance of Piles in Sand 
Weight of Timber YWt and I)r\ 

rti- i 

I I I i I 1 ■«. It! ... ... ... ■•• ... 

Stability and Flotation of Rectangular Pontoons 

Shearing Strength of Mortar .Joint 

Strength of Brickwork ... 

Holding PoweT of Bolts in Masonry 

I tement and Concrete 

I >uml'ilit\ of [ron in Water 

Weight of Kentiledge \'<>i Counterweigh! 

Aggregates in Concrete in Contact with Steel or [ron ... 

Superimposed Loads on Floors of Buildings 

Properties ol Materials in Common I 3e 

Weights of Materials and Merchandise... 

Specifications : 

Revised Specification for the Structural Portion of Heavy ( lantilever Cranes 
Genera] Specification for Structural Steelwork for Travelling Cranes.. 
General Specification for Bridges: Material for Bridges 



Railway Bridges (includin 
and Swing Bridges) .. 
Road Bridges 
Clearances for Bridges .. 

I ri neral Specification for Workshop Buildings ... 



Index 



T 



res 



PA(.E 

373 

.37:; 
374 
37-'. 

375 
376 

378 
381 1 
380 
38 1 
38 1 
385 
385 
386 
390 
301 
393 
393 
396, 398 

3JM.I 
400 

400 

ion 

401 
103 
404 
104 
407 
407 
410 
411 
412 
412 
414 
41(5 



ties 



■ ■ * 



'■1 



Pi 



- 



119 
422 

127 

t28 
443 

1 51 » 

151 




fir 



3 



List of Illustrations. 






-. 



MS 












x* 



\. • 



ft 






Portrait oi Sir William Arrol, the Foukdbh 



Pronii - 



HlSTORICAl : 

Map Showing Position of Works in Glasgow . 

The Bothwell Viaducl 

Roller Path of Large Swing Bridgi 

The Forth Bridge 

The Tower Bridge 

The Redheugh Bridgi ovi r the Tyne a1 Newcastle 

T\ pica) Bridge Piei - 

Air Locks Used in Sinking Cylinders under i »n — I Ui 

The Naval Engine Works ol Messrs. William Beardmon md Co., Ltd., al Dalmuir 

Parsons 1 Marine Steam Turbine Works 

I >E>< EtlPTION 01 W< IRKS 

General Offices of the Company al the Dalmarnock Works, Glasgow 

A Recen iug Yard b n Material , 

One of the Machine and Erecting Departments 

Plan of the Principal Girder-Machining and Erecting Shop 

1 'iir oi the 1 •rawing < >ffi< es 

The Making of Templates 

Cutting Bars and Angles foi Girders 

Planing the Edges ol Plates for Girders 

Hydraulic Machine for Forming Knee Bars, etc. 
Machine and Dies for Forming Small Unite of Girders 
Battery of Twenty four Radial Drills for Girder Work 
Riveting- 
Large Press for Forming Plates of Various Shapes 
Building a Scherzer Rolling Lift Span 
Erecting Shop in the Engineering Department 
The Brass Finishing 1 lepartnienl 

View in Powei Station ... 

Hydraulic Engines in Power Station 
One of the Erecting lards 

Bridge Building : 

Main Span of the Landore Viaducl 
Firsl [ron Bridge ever Erected 
The Forth Bridge 

W Chin fr fCai ' on the South-Wesl Pier'of Forth Bridge 

|^ l ;° rf Camon with Air I^ks a«d Working CI be, 

I lie 1 lei Erected to Full Keighl 

Di ^» Crating the Buading oi u,„,w- „,„,,- ,,._ 






I 
11 

15 

21 
25 



28 
30 
31 

35 
37 

38 

II 
II 

i:; 

44 
15 

IT 

1!» 



■■.«• 
61 

■; 

69 

;i 



. 



LIST OF ILLUSTRATIONS. 



IX 















Rkidge Bttildikg (continued) : 

The Southern Approach Viaduct 

The Tay Bridge 

Transferring Girders from Old to New Piers ... 

Raising • lentre spun Girders on to New Piers by Hydraulic Jacks 

The Tower Bridge, with Bascules Closed 

The Tower Bridge, with Bascules Raised 

The Bridge Across the Nile from the Island ofRodah to Ghizeh 

Tin- Swing Span Open for the Passage of Boats 

One of the Two Bridges between Roduli Island and Cairo 

The .Main Bridge across tin- Nile with its Test Load ... 

\ iew <«t \.\ i-.iv Bridge during Erection showing Pier and Double Deck 

First Stage in the Building of the River Span... 

Final Stage in the Building «<f tin- River Span 

Hydraulic Stressing Gear on Temporary Ties . 

The Scherzer Rolling Lilt I Iridic "\-«t the Swale, closed 

The Scherzer Boiling Lift Bridge over the Swale-, opened 

The Viaduct over the River Barrow 

Genera] View of the Viaduct over the River Barrow ... 

View along the Bridge ... 

Tin- Caledonian Bridge over the River Civile at Glasgow 

Section showing Old and New Redheugb Bridges 

Redheugh Bridge 

Tin- Xorth Bridge, Edinburgh, with Waveriey Station under Reconsti 
Sudan Railway Bridges. Girder Spans Completed at the Glasgow U 

Transport 

Swing Bridge for Railway over a Canal 

The Dalginross Bridge at Comrie 

Bridge over Manchester Ship Canal for Railway 

Roller Ring for Stockton Heath Swing Bridge, Manchester ship Cans 

Caisson for Pier Ready to he Lowered into Position ... 

Launching One of the Face Ribs into its New Position 

General View of Works, Lm.kin^ South-En-i ... 

Rib Just Launched, Showing Temporary Girders used for Steady] 

Launching ... 
View of the Walney Viaduct from Vickerstown 
View from the Dolphin of Roller-Lift Span Open for Steamship Traffic 

Stru< ii i:ai. Steel Wobk : 

Steam-Turbine Erecting shop at Clydebank Works ... 

Moulding Lofl at the Clydebank Works 

Sawmill at the Clydebank Works 

View • »f Building Berth, with II. M.S. " Agamemnon " 

Details of Building slip al Beardmore's Naval Construction Works, Dalmu 
William Beardmore and Co/s Boiler Works ... 
William Beardmore and Co. 'a Machine Shop ... 
View in Beardmore's Boiler Works 



Facing 
Facing 

Far i ik / 

Facing 

Facing 

Facing 

Faring 



uction 

orks Readj for 



■ 

n 



Ril 



I' i ring 

Feeing 

Facing 
During 

Facing 
Facing 



• i * 



. . . 



PAOl 

- — 
i i 

81 
83 
85 
89 

i»l 

93 

in 

95 
95 
97 
LOO 
101 
10-2 
105 
107 
111 
1 1 3 
116 
117 
120 
121 
1 25 

127 

129 

131 

1 3 I 

135 

136 B 

136 b 

136 < 

1 :t6 c 
138 

L38 a 



147 
149 
L49 
151 
L53 
L5 I 
155 
157 



?**. 



»*»■ 



.Of 



I 



1 



Kfc 



& 






II 



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I 



• 



\ lid. ;i1 

Facing 



x LIST OF [LLUSTUATIONS 

Sua , ii i:\i Steei Work (continued) : 

Vickers' Foundry for Marine Work a1 Barrow-in-Furness 

Vickers' Foundry for Ordnance al Barrow in-Funiess 

One of Vickers* Ordnance Workshops ... 

Section Showing Overhead Travelling Cranes 

Shipbuilding Berth Equipment al Messrs, Harland and W olfF - 

Building New Engine Works for the Tranmere B Developmenl Co., Ltd., 
I tirkenhead ... ...... 

Tin- Kn^iiie Erecting Sliop al Fairfield 

Tin- ISoileT Sho] i -it Fail Held 

Tin- Covenl ry ( Irdnance Works in Course of Construction 

Glenfield and Kennedy, Ltd., Kilmarnock, Foundrj 

Engine Works of Wallsend Slipwa) and Engineering < Jo,, Ltd. 

Boiler Shop of Wallsend Slipway and Engineering Co., Ltd.... 

Engine Fitting Shop of Scott's Shipbuilding and Engineering Co., Ltd. 
Boiler Shop si Yarrow's Works, Poplar 

Cross-Section through the Shops al Yarrow's, Poplar 

Heavy Machine Shop al Farrow's W\ >rks, P< »plar 

Farrow's New Engine Works al • rlasgow iiH lourse of Er< ction 

Farrow's New Boiler Shop al Glasgow in Course <•.' Erection... 

Parsons' Maim-' Turbine Machine Shop 

Marine Boiler Shop at Babcock and Wilcox, Ltd., Renfrew ... 

Boiler-Erecting Department, Looking North; D. Rowan and Sons, Glasgow 

1;,,,IlT Shop, East Baj ; Lighl Plating Departmenl ; I >, Rowan and Sons, Glasgow ... 

Fitting Shop of G. and J. Weir, Ltd. . 

Foundry of <i. and J. Weir, Ltd. 

. . . 

Imperial Tube Works, Coatbridge, of Stewart and Lloyds, Ltd 

Erecting Shop of tfeilson, Reid and Co. (no\i North British Locomotive Co., Ltd.), 
Glasgow 

Newburn Steel Works of J. Spencer and Co Ltd 

" • • • 

Works of Marshall, Sons and Co., Ltd., of Gainsborough 

The Bow Electric Generating Station 

S,,: '-" Gilding al Guinness's Brewerj in Course of Construction, January 1. 1904 
Storage Buildings. Guinness's Brewer} in Course of Construction, Maj 3, L904 
< ' 1 1 i 1 1 1 1 1 . ■ \ Stack at Guinness's Brewen 

Mechanical Engineering Productions: 

SJT 1 ^^ ^^^ Pum P s a t the Vickers Ordnance Works at Barrow-in-Furness 
Electrically-Driven ffydraulic Pumps 

H y draul ^ c Ji ^ Crane with Racking and Slewing Motion al the CTorth British Loco 
motive \\ orks, Springburn 

Crane for Supporting Bydraulic Riveters and Other Work 
ForgeCrane ... ... _ 

'^7;-" i^-r si,,., •,,,,; .;, , ■,•;;,.,,„ „,„, l ,x^,r., 1 ,,„„„ 1 „,w., l , 

oi Messrs. \\ ,li„„„ Beardmore I Co. Ltd 

■\ fypical Shipyard Crane at Messrs. John B, a and Co/s Clydebank Works 



1 
I 

160 
I6t i 

L60b 



-~* 









rid 






LIST OF ILLUSTRATION'S 

Mechanical Engineering Productions (continued): 

3-Toil Pedestal Crane al Messrs 1 Jan-lay, Curlr ami Co.'s Slii|t\;ml 

Crane at Viewers' Work- al Barrow-in-Furness 
I'll.- "Scissors 1 Type of Hydraulic Riveter 
The " Bow ' Tvpe of Hydraulic Riveter 
Machine for Riveting Light Steel Pipes 
"Hinged' Type of Hydraulic Riveter ... 



XI 



Riveting a Cunard Liner at the Clydebank Works of 



Messrs, John 



Ltd, ... 

Eletorl Charging Machine at the IVrktmi Work- of the Gas Light and Cok< 
Charging Machine at the Vauxhall Worksof the South Metropolitan G&s 
Machine for Withdrawing Coke from Retorts 
Machine for Cleaning Ascension Pipes of Retorts 
Machine for Cleaning Ascension Pipes of Retorts 
Machine for Cleaning Ascension Pipes of Retorts 
Coal-Elevating Plant 
Motor for Working Conveyors ... 
Traversing Motor 
Capstan Type of Hydraulic Motor 
No- 1 Standard Stop Valve 
No. 2 Tapered Flat-Faced Valve 
No. 3 Standard Slide Valve 
No. I Standard Piston Valve 
No. 5 Standard Double-Spindle Lift Valve 
No. 6 Hose < loupling 
I [ydiaulic Stamping Press 
Lighl Power Stamping Press 
Hydraulic Pipe Flanging Press ... 
Portable II ydraulic -lack... 
Hydraulic Machine for Forming Kjiee liars, etc. 
Machine and Dies for Forming Small Units of Girders 
Cutting liars and Angles for Girders 

150-Tull Elrctrir Ilaiiiliirl-II.a.l Crane . 

L 50-Ton Electric Hammer-Head Crane... 
The Roller Track of 150-Ton Crane 
Details of Roller Track of 150-Ton Crane 
Machinery of 150-Ton Electric Hammer-Head Crane 
Electric Derricks for Shipbuilding Berths 
Sinking a Pit Shafi by Compressed Air 
Air Locks for Sinking Foundations 

A.PPEXIMCE8 : 

Diagrams for Calculation of Beams: 
Figures 1 to 30 

C<>ntinu«>u> Girders: Figures 1 !•• 6 

Special Cases : Inclined Cantilevers and Beams ... 



l\r> iwn 





PAGl 


, . 


■_' 2 1 


. . ... 


221 


• 1 . 


22 i 


- ■ • 


225 


. 


226 


• ■ ... 


227 


and Co., 




... 


229 


Co., Ltd. 


233 


Co., Ltd. 


23S 


> > . . ■ 


237 


■ ■ ■ * ■ 


238 


... 


239 


• ■ > > > 


241 


. . 


243 


. ■ * 


2 1 5 


... 


2 1 r. 


> . . ■ . 


245 


> . 


217 


* . . . . 


247 


* * . 


2 is 


. . . 


248 


■ > • 


249 


■ . ■ . > 


249 


• . * * • 


25 1 


. . ... 


253 


■ . . ■ 


255 


• > * 


256 


• • * ■ . 


25 7 


* * ... 


258 


« > • . . 


259 


• » . - ■ 


261 




263 


• ■ 


265 


■ > . . t 


2«i7 


. ... 


269 


• 


27:'. 


. . . 


275 


• ■ ... 


27 7 



. . . 



■ • 



Moving LoacL 



280 
303 
306- 
311 



300 
305 

3 1 2 
317 







l.4kl 






& 




t f 



Ml 



LIST OF ILLUSTRATIONS. 






Appe mutes (continued) : 
Influence Lines ... 
Columns with Eccentric Loads ... 

Portal Bracing 

Columns 

Eccentric Loads 

I ieneraJ Formula 

Brain.- of Solid ( Iross Section 

I leflection of Framed Structures 

Combined Stresses: Cross Bending and Direct Tension oi Compression 
Si renstb of Rings 












I ;• -.11 i i iu Plates 
Bearing Pressure 

Approximate Weights of Travelling Cranes 

Wind Pressure 

Hollow Cylinders 

Friction of Hydraulic Rams 

Concrete Foundations 

Stability and Flotation of Rectangular Pontoons 

Shearing Sum-tli of M..rtar .loint 

Traction Engines and Boiler Trolleys 
Sta ml; ml Clearances for Bridges 












pagi 
318—325 
326 331 

:;:;j— :; 

340 342 
3 1 1 

345 363 
36 I 

366 369 
371 
372 
374 

377 
381 

393 
39 I 
399 
103 

404 

I 13, III 
150 



M 



-» 







I 

3 






Errata, 



Page 260, last line, "page 737" should be "page 803." 

Page 287, line 19, for "measure x from <■/' read "measure x from C." 

Page 2ss, line -0, for "measure x from <•. /•'?«</ "measure x from C." 

Page 299, line 5, Expression (ii) for M r . for " - w ft a; 2 , /•"'«/ " + kj 6 xV j 

Page 311, line I, /<>/• "supported at B," read "supported at A." 

Page 329, line 7, for "M B = - RcC," mod «M B - - E^c." 

Page 329, line 7 at side, for "is = - R u ," read "is = + Ii„." 

Page 372 (figure) Strength of Rings. Point C is at the centre of the thickness of tlie 

ring in a diametral plane at right angles to tin* links. 

I *■_:•* 37(5, lint* 11 from bottom, for "above*" read "following." 



3 



. 



*& 










V 



Foundations of Success. 



rjlHE high position attained by Sir William Arrol and 
x Company, Limited, is largely due to the fact that 
much of the work they have done has been of special 
difficulty and of great magnitude. It has thus made 
demands on them that could only be met by much 
practical engineering skill and by the evolution of special 
appliances. 

As example, we may take the case of bridges — 
perhaps the most widely known, but not the only, branch 
of the Company's business. The designer may formulate the 
laws of stresses, and conform to them in jjlans and sections 
of piers and girders, and struts and ties ; but the embodi- 
ment in material form of the most perfectly-conceived 
ideas requires the solution of many difficult problems by 
the constructor. Such work has often to be carried out 
in difficult situations or against adverse natural conditions. 
Unstable or uncertain strata and abnormal elemental forces 
may combine to exercise the resource and patience of the 
builder. Indeed, many schemes, which by virtue of their 
boldness are regarded as triumphs of genius, have largely 
depended for their success upon operations, of a more or 
less novel character, connected with construction and 
erection ; and for these special methods and apparatus 
have had to be devised by the builder. He is thus a 
necessary corollary of the designer, and deserves an equal 
measure of credit. 

B 




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•_> Great acini \ \ mi- \ i-. 

The originality displayed by Sir William Arrol and 
his colleagues in the Company in the execution of greal 
and difficult works lias, on more than one occasion. 
created new precedents in engineering practice, and to 
this quality there has been rightly attributed the satis- 
factory completion of several world-famed structures. The 
invention, in 1875, of a machine for drilling all the 
component plates and angles of the booms of heavy 
girders, and the construction of hydraulic machinery 
for riveting them together with a rigidity impossible 

to manual effort, were typical preludes to the great 
achievements in connection with sub-aqueous founda- 
tions, and the erection of such structures as the Tay 
Bridge, the longest viaduct in Britain : the Forth 
Bridge, the greatest cantilever structure in the world; 
the Tower Bridge, with the heaviest bascule yet made; 
the Barrow Bridge, in Ireland, with its foundations 
extending 117 ft. below high-water level ; the Swale Bridge, 
in Kent, with the heaviest rolling-lift span in England : 
the rebuilding of the high-level Redheugh Bridge over 
the Tyne at Newcastle, without interfering with traffic 
on the old structure; and the erection of the new 
Caledonian Railway Bridge over the Clyde at Glasgow, 
with its large foundation caissons and superstructure of 
11,000 tons. These and other great undertakings which 
need not here be specified have successively contributed 
towards winning for the Company a prominent place in 
™ world's list of constructional engineers, and have 
added to the engineering renown of Great Britain 

The beginning of Sir William Arrol s Works dates 
'rom is, L >. when the nucleus of the present large establish- 
ment was commenced in the oast end of Glasgow, amidst 



hay and cornfields, whei 



e now a great industrial community 



ArmI 



aa.| 



THK FIRST WORK I'NDKRTAKKX. 



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surrounds the Company's extensive shops. And here it 
may be parenthetically stated, in order to obviate misunder- 
standing, that Sir William Arrol has never been associated. 
in name or otherwise, with any other bridge, roof, or 
constructional steel works in Scotland than those of Sir 
William Arrol and Company, Limited. The map repro- 
duced below, showing the location of t he Company's 




Map Showing Position of Works in Glasgow. 

Dahnarnock Works, and the tramway routes from the 
various railway termini in Glasgow, may assist the visitor 
in finding his way to the establishment. 

The first work undertaken at the Dahnarnock estab- 
lishment was boiler-making : and. as indicative of the 
fact that, then as now, sound workmanship was the aim 
realised, it may be mentioned that when twelve of the 
first boilers made were recently removed from the works 
of the Steel Company of Scotland, because higher steam 
pressures were necessary, they were found to be in good 








THE BoTHWKU. VIADUCT 



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.- « 









condition after their thirty years' service. Girder work 



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■•—'•■ ■ >"V" >...... ...,.o DW T1MJ, uinici WHIR 

as entered upon at an early period, and the first notable 

attract was for all the bridges of s of the importan< 

Edinburgh suburban railway lines. The larger spans 
ranged up to 60 ft. and 70 ft., to carry the railway over 
the water of Leith. What a contrast is presented by the 
1730 ft. spans of the Fm-t I, Bridge, also in the vicinity 
of the capita] of Scotland .' 

A prominent success followed in the building, in 1875 
of the Bothwell Viaduct ..ver the River Clyde for the 
Hamilton and BothweL Branch of the North British Rail- 
way. An engraving of the viaduct is reproduced on the 
opposite page. This work consisted of seven spans of a 
total length of 727 ft The chief interest in this case was 

associated with the method of projecting the, tinuous 

g*dei« across the river, from pier to pier; this was do,,,. 
from one shore on rollers, actuated by ratchet-bars This 
P-ed-e is now largely adopted, but'at thatea^ s£g 

"itlnrt/C:!. '"• - ^ cities Uld 

-"tract for building the he vv , f^ "* 

to carrv their ,, ■ , } hlCt a(TOSS tlle Cl 7^ 

cent^rstiti :;■;,, :;;: of Th fn **> *. pre L 

the largest of 200 ft S a T "^ ? *™ W 

negate weight of Cted^h, f 5 ° * ^ 

tons. The oi.,1,.,., ' m tl,e structure was 3000 

A "« gilders were verv hpnvx- +i , . . 

cases fourteen thicknesses in h, ' T &mg W S °" ie 

i'> the interests of str n ■■ ' * ^ AS tt W " S desired > 

to drill all the pt^ eCOn0my ° f manufacture - 

operation, instead of sem ,.J, a C °'" ,,lete Section at ™ e 

'"'"l—'t plate leT J PUnchln * ^ h ^ »' «* 

1 ^ the Company devised a drilling-plant 






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nJK ORGANISATION OF THE RNG1NEERING DKPARTMRN1 



for carrying ou* these operations on the girders. At the 
same time, hydraulic power was introduced for closh _ 
tlit 4 rivets through these heavy multi-plated booms The 
hydraulic pressure for closing the rivets, equal to 1000 lb, 
per square inch, necessitated careful research before a 
satisfactory flexible supply-pipe could be made; but, this 
difficulty overcome, the system was soon extended, and 
by L880 there were many applications of hydraulic riveters 
in shipbuilding and boiler-making, as well ;i<. in bridge 

and other structural steel work. 

It may be interpolated here that, in 1905, the Company 
raised bodily, by hydraulic jacks, to a height of 'A ft . the 
girders and decking of this bridge, some of the spans 
weighing 800 tons. This was done so that the rail level 
would coincide with that of the new bridge constructed 
alongside. The latter is 752 ft. long, averaging 120 ft. in 
width, and the steel work weighs 11,000 tons. 

Tin- experiments necessary for the inventiou of the 
drills and riveters, and the evolution of new forms of 
tools suitable for the growing variety of work, resulted 

'ii the extensi f the engineering branch of the 

Company's Dalmarnock establishment; and. with that 
enterprise whirl! has always characterised the concern, 
experiments on pumping plant were undertaken, so that 
ultimately the Company produced all the units of an 
Hydraulic - power plant, as well as many tools ha- the 
utilisation of such power. 

Several of these tools w ill be mentioned when we 

""''' t0 ,l ;' srn1 "-- the engineering department of the 

«, and presently reference will he made to the im- 

;"* mechanical appliances connected with the sinking 

founit^riht v . ***•« ° ther sub - aqueou8 ' 

ne ex tensive experience of the Company 












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lilt FORTH BKIIm 



has enabled them to effect many important improvements 
in air-locks. 

The making of the machinery for working opening 
spans of bridges is another notable department. The 
engraving on the previous page shows the roller-path, etc., 
for a large swing span. 

Another branch is the manufacture of hydraulic and 
other cranes, the designs of whirl) have been pei bed 
as a result of practice in their use. A kindred depart- 
ment i> the manufacture of coal-conveying and _ - retort 
charging appliances, wherein hydraulic power is utilised 
with an efficiency he^otten of long association with this 
prime mover. 

To return to the chronological narrative, the Company 
in the 'seventies constructed several important bridges at 
home '""l abroad ; hut the firsi structures whi call 
for special mention are the new Tay Bridge and the 
Forth Bridge, whirl, were built simultaneously. 

The contract for the Forth Bridge, was signed in 
December, L882, and the work was finished in 1890: an 
achievement the merit of which is proclaimed by the fact 
that the six cantilevers of 680 ft., with their res itive 
piers, and the approach viaducts and the abutments, make 
up an aggregate length of 8295 ft. v in. of iron and steel 
alone there were built into the structure over 60,000 
tons, rhe building of the immense members forming the 
( " nt : k ' Vr,> - P leis > <*=•, involved the design and construction 
<* the Company's works of many ingenious maehine-tools 
and appliances. 2 

The aew Tay Bridge is of equal interest, not only 

r;V tS ««* 'ength-lO?!! It-tat in view of 
fixities associated with the construction of the 













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INK I \ i AM' H'W I R UKIIm.I S, 



piers. It was here thai the Company introduced od a 
large scale the system of pontoons for sinking ssons 1 
These were made up of a scries of water-tight tanks with 
intervening spaces through which the cylinders of the 
piers were sunk. To support the pontoons, columns or 
legs were passed through apertures at their corners. These 
columns rested on the river bed, formed guide posts, and 
were fitted with means whereby the heighl of the pontoon 
could be regulated. These working platforms, which were 
raised or lowered by hydraulic jacks, carried all the 
machinery and gear i'm the building of the piers The 
cylinders were constructed in convenient lengths on 
the shore, conveyed to the pontoons, and raised bj cranes 
to the working platform. On being lined with brickwork 
^d loaded, they were lowered by hydraulic power into 
position. This proved quite a satisfactory procedure, and 
the eighty-five piers were easily and quickly completed. 
I,,1S bnd g e -S* William Arm! and Company, Limited. 
were concerned only with the second structure across 
J 8 . ,th ; jt ^-necessitated the use of 27,370 tons 
ot iron and steel, besides other material, for the super- 

Z \ U r buildin 8 of thi « bridge, begun in L882, 

w.i.s (-..inplftod in 1887. 

should"! DeXt , outstandin g structure to which reference 
Company 'Z-k 'is' thThHH^ , '- t "»-' -».-.-« «.f tl.e 

^tructedbvZo Dhewholeo1 the girder work was 

The Tower ivi i ' dmded into seven s P ai 

'^'- commenced in L886 and completed 

J // "' / - wl. xij,,.. p,^'!;';, 1 """ """' : , "'' x " iv - Page 689 ; vol. xlii., i 14. 

''"''■ V ' ' vi - '"-" ^'^ H» u 8 r , , 

"'■ " • '■ ! i and >oL Ivii., page 852. 






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M vN( ill -I I i: SHIP I v\ \l. HR1IMJI 



in [894, has three spans: the side ones, on the suspension 
principle, are 270 ft.: and the centre, the bascule span, is 
200 ft. The two river piers, 70 ft. wide, accommodate the 
machinery for raising and lowering tin* bascules. Then also 

• • 

support towers, which rise to a height of 120 ft., to carry the 
suspension chains and two high-level foot-passenger bridges. 
These upper platforms are reached l>\ stairways in the 
towers, the idea being thai they should be used for 
passenger traffic when the bridge was open for the passage 
of river craft. Experience, however, has shown thai the 
bascules, although they weigh each about 350 tons, are 
opened and closed so quickly that the interruption to 
traffic across the bridge is of such short duration that 
passengers prefer to wait rather than use the high-level 
bridges. The entire steel work, aggregating 10,000 tons, 
was carried out by Sir William Arml and Company. 

The Company were also responsible for twelve of the 
largest bridges on the Manchester ship Canal. 1 Most of 
these are of outstanding importance. The largest of the 
viaducts carry the London and North-Western Railway 
^. ross the River Mersey and the ship canal near 
amngton. Over each water-way there is a girder 
span, and on each shore a masonry arch. The spans are 
^ 160 ft and the girders have a total length of 173 ft, 
™« *fgbt at the centre of 21 ft, tapering to 14 ft. at 
of „ • ""' approach arches of masonry are each 
'• span. Near Partington there is another large 
( . (II11 f, '"' r:m - vi "~ ""' railway of the Cheshire lines 

' "inituttcv over Mm P,v -vr 

is l50 ft . t,u ,uu ' r Mersey. There the centre span 

also for c-u," v - " si,, ;" S| ' aUS "'• H» * A third bridge. 
i.-„; & ,. ..'. • 8 a nnl ^>y. lias tlnv,. main eirders each 



• lon gj spaced at 38 ft , * 

i *c ^b tt. centres 



' , ' N " ,N|,,;,N| - vol, lvii.,page 111. 



•-•>; 



A TYPICAL SCHERZBR BRII>fIK. 



13 

























Of the seven large swing bridges needed for road 
traffic over the Canal, 1 Sir William Arrol and Company 
built live, and these are all of the heaviest type. In all 
cases the span is 120 ft., but the width varies; the 
weights of the swing spans range between 550 and 1350 
tons. The heaviest of the bridges are those near Latch- 
ford and near Warrington, the road in these cases being 
36 ft, wide. In each instance the swing span rotates on 
sixty rollers, on a circular-path 38 ft. 9 in. in diameter, 
constructed on the canal bank. Such a roller-path is illus- 
trated on page 7. Being quickly operated, these swing- 
bridges have practically nullified any inconvenience that 
might have arisen from the existence of a ship canal 
through a country where traffic is very extensive, owing 
to the adjacence of so many mines and factories. As 
indicative of the extent of work carried out by the 
Company in connection with the Manchester Ship Canal, 
it may be said that it required the use of about 
10,000 tons of constructional steel work. 

A typical Scherzer roller-lift bridge is that built by 
the Company in 1904-1905/ to carry the South-Eastern 
and Chatham Railway, and the public highway, over the 
Swale, in Kent. The lift span is 65 ft. in length, and 
of 520 tons in weight, including lead and iron balance 
weights ; yet the time taken to raise it is only 50 seconds, 
and the power required 9 brake horse-power. 

Many other bridges might be similarly described, 
but we content ourselves in this historical review with a 
reference to four more structures : one over the River Tyne, 
another over the River Wear, and two viaducts in Ireland. 

The first-named, built in 1900-1901, at Redheugh, is 

1 Engineering, vol. Ivii., page 118. 

- Ibid., vol. lxxix., page 762. 




HvSJ^r* 



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14 



BR1D0I OVER ME l>\' KSV TNI WEAR. 



forroad traffic between Newcastle mid Gateshead. Theold 
structure had. in the firal instance, t<» Ik- supported on 
timber trestles carried from staging around the <>ld piers, so 

that the new piers could he sunk on the sam< site. 

Each <>t' the three new main piers consists of four 
cylindrical caissons, sunk t«> a depth of 65 it. below high- 
water level. Into the four spans — two over the channel of 
the river, each of 248 ft. in length, and two from the shores 
of 1(1!) ft. in length — there was worked 2750 t<»ns of steel. 
They were buili from the new piers cantileverwise. The 
roadway is 23 ft. wide, with footpaths on the outside of 
the lines of main girders. The main members of the new 
bridge were erected parallel to the old girders: one of them 
on a footpath, and the other outside of the old girder. 
They were at a slightly higher level than their original 
seating, so as to interfere as little as possible with the 
old bridge. The transverse-girders having been constructed 
in trenches across the roadway, the main girders were 

lowered and the new decking built. The old spans were 

then removed, and finally the new- bridge was moved 
laterally into its correct position, taking the line formerly 
occupied by tlir old structure.' 

the Wear HHdge is in course of construction at Sun- 
derland, and is designed for two decks; the upper for the 
double line of railway, and the lower for the roadway, 
with footpaths outside of the girders. The height will 
gwe a clear headway ahove high-water level nf 85 ft. The 
total length of the bridge and approaches will be 1560 ft- 
u» river span is 330 ft. long-so that the girder steel 

J <• » very heavy, totalling 9000 tons. The method pro- 
£ *V or Placing the heavy central girder in position is 

gnious,and suggestive of the resource of the Company. 

' En <"kbkrikg, vol. Ljutit., paces 550, 644. 



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The shore spans having been completed, towers are to be 
erected upon the river piers, the shore girders being 
utilised for anchorage. The girders for the river -pan 
will he constructed from each pier as overhanging members, 
and will be supported during the process of erection l»v ties 
from the tops of the towers. When the halves thus con- 
structed meet in the centre and are joined, the temporary 
supports will be removed, Hen', as in many of the modern 
bridges, chief interest was associated with the founda- 
tions. One of the piers necessitated the sinking to a 
depth of 75 ft. under high-water level of a rectangular 
steel caisson 63 ft. long and 35 ft. wide. This operation has 
been carried out under air-pressure in a satisfactory way. 

The bridges over the rivers Barrow and Suir,' built 
in L905-1906, are also notable for the greal depth of 
foundations as well as for their Length. The Barrow 
Bridge is the longest railway structure in Ireland, being 
2131 ft. long between the faces of abutments, mad.' up of 
thirteen spans each of 14s ft. j„ the clear, with a swing 
span over the channel, giving a passage 80 ft. wide for the 
",' a . ftr '."' each side of tin- centre dolphin. The Suir 
ridge is L205 ft. long, and in tins case the opening span 
w of the Scherzer roller-lift type. The piers of the Barrow 
Kndgeare founded in many cases at a depth below high- 
" ilt Y 'evel of from loo ft. to 117 ft., the latter the greatest 
aeptn yet readied i„ compressed -air work for bridge founda- 

\vTJ!\ iv Unit, ' (1 K'""' 1 " 1 " 1 ' The maximum pi ssure 
as 4*5 lb. per square inch above atmosphere. 

w work was successfully carried through at this 
*«« depth, and under this high ul ^ This is M 

' SblTftV 01 - L^- '«" 673 ' 716 ' 78 °. ««• 

uitl < the Hawkesbury 81 ^-/ 1 ^ P v l "'"' 1 "" 1 '"'' brid g e foundations was in connectiou 
le vel, but in this ca i ,1""" '!' Ne * South WaIes . namely, 162 ft. belov i-wriw 

"' w,,,k "as not .lono un,|, r compressed air. 



. 



Ml 



FOUNDATION WORK AT GREAT DEPTHS. 



17 









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one would expect, in view of the great experience of 
the Company in such work ; no British firm has carried 
out sucli extensive operations in this department of engi- 



neering. 



Although subaqueous foundations were formed in 
the later years of the eighteenth century by means 
of diving bells, the use of compressed air for excluding 
water from working chambers in caissons dates only from 
the latter half of the nineteenth century, and the first 
application for important work was probably in connection 
with the building f the St. Louis Bridge in 1870, where 
the deepest foundations are 108 ft. below water level. 1 

The success of the process in the sinking of the 
caissons of 70 ft. diameter for the piers of the Forth Bridge 
in 1884, established the practice in this country, and 
since then it has become very extensive. In 1870 Sir 
William Arrol and Company carried the piers for the 
Caledonian Railway Bridge across the Clyde at Glasgow 
to a depth of 70 ft. below high-water level, and since then 
they have worked down to 85 ft. in the same river for the 
piers of the new railway bridge alongside the old structure, 
and also for the founding of quay walls for Glasgow 
Harbour. They worked to a depth of 65 ft. in the Tyne 
for the piers of the Redheugh Bridge, and to a similar 
depth in connection with the Swale Bridge ; while on the 
Wear, as we have already stated, their operations extended 
to a depth of 75 ft. below high-water mark. Through 
the fine sand of the Nile they worked to 75 ft. below 
Low Nile, so that the work on the Irish river is only 
the natural development of former achievements. 

It will be recognised that compressed air offers an 

1 See "Sub-Aqueous Foundations, with Recent Examples of the Use of Compressed 

Air," l.v ■!. E. Tuit, M. Inst.CK. 

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nil. M. BH1P0I PIKRS \\|i . USSONS 



enormous advantage, because in the event of the cylinder 
meeting an obstruction in the process of sinking, such as 
boulders or sunken barges — as, indeed, was experienced in 
the Nile — there is no danger, and bul little delay to the 
progress iA' the work. 



rety, and with 1 v likelih I of overcoming il 

advantages of such obstructions as those referred to. 

The steel usually extends up to within 10 fl or L 2 ft. of 
the bed of the river, the walls for the remaining height, 
where subjected to the action of water, being of casl iron. 
isual y, a lining of concrete is ,,„, in during the process 
ot sinking as illustrated in the case of the typical bridge 
I>h;i on tin- opposite page. This illustrates a pier of the 
^nhn.i.,. already referred to. The most recent practice 
™* oeen to form in the inside of the concrete lining a 
""i casing as ahown, so that the cast iron is nut subjected 
to any pressure from within. A temporary shaft of steel 
■ a» continued to the top. and the air-locks are carried 
• " order to distribute the weight of the tem- 

on the tot trh the l0, ' l<S ' 6tC -' girdera are constructed 
to it. The ° cast -i r <>n cylinder, and secured by bolts 

the InMr* ! mnershaft « suspended to these girders, while 
The d^ , SUPerP ° Sed U P° n fchem " 

U * ex Perience IJl """^ haVe Wn evolved fr ° m 
page 21 Tl " e arran gement is well sh o on 

foundations fowl V "' XVS iUustrate the ™>rk of sinking 
dock of the m ~? P16rS fov a 15() - tl "' jib-crane at the 

^ydebank Shipbuilding Yard of Messrs. 



IVI'ICAL BRIDGE 1'IEKS. 



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MifTtom Door 



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\MdUruJ Lock 
Bucket 

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UK uoi K S i OB SINKING Dl I P VO\ NDATI05 



.| ( ,hn Brown ami Co., 1-td. The man-lock is placed 

next the cylinder, and the material lock above it, with 
an overhead gear tor raising the buekets out of the lock 
The man-lock consists of two chambers; tin- material- 
Lock is (»n the same principle, bul lias horizontal doors 
The doors are fitted with locking gear, so that when a full 
bucket is raised, the lower compartment is closed to the 
cylinder before the bucket can be passed to the upper 
compartment. The bucket travels through the man-lock, 
but the compartment tor the ingress am! egress of the 
workmen is entirely independent of the shaft through 
which the material passes. The doors are manipulated by 
rack - and - pinion -ear. actuated by a hand-wheel. The 

buckets are raised ami lowered by steam-winches placed 

outside, the shaft to the winding - drum inside passing 

through an air-tight -land on the side of the material- 
lock. 

Experience has also enabled the Company to formulate 
definite regulations, so as to minimise the chances of 
the men suffering fro,,, compressed-air illness. So long 
as the pressure in the working chamber is not above 
30 lh., the men are permitted to work eight hours per 
•lav, but when this pressure is exceeded, the days work 
is limited to six hours <„• k, ss . ;,, both ease, in two 
shifts, with an intervening period of about two hours. 
Is workin g "me of course includes the period of passing 
trom the atmosphere to the high pressure, and ma vend. 
'th high pressure the period prescribed is twenty minutes 
^ theformer ' *«'<! twenty -five to thirty -five minutes 
the 1 , * tePj l >ass; W As soon as the men are out of 
' ' lmt coffee is supplied, and they are advised not 
o go immediately into the cold air. An effort is made 
secure workmen who have lived temperately, as it i 




DESIGNING DEPARTMENT. 



21 






found that they are least affected by the sudden changes 
in pressure. 

The bridges which we have described were designed 





Air Locks Used in Sinking Cylinders under Compressed Air. 



iff 



jjf 



by eminent engineers; but, in the interval, Sir William 
Arrol and Company had developed a designing department 
which has been a large factor in their continued success 
as an industrial concern. The reason, perhaps, is that it 
has been found conducive not only to efficiency, but also 
to expeditious work, that structures should be designed 



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SCO ESS IN DESIGN !fl INTERNATIOJi VL I OMPI PITIO 



to conform to standard machine-shop practice, as well as 
with (hit* regard to strength ; and to this ia doubtless 
attributable the adoption of the Company's design in many 

instances. 

Some typical examples of bridges designed, as well as 
built, by the Company are given in the Table in a subse- 
quent page; and here reference need only be made t<» a 
large series of bridges constructed within the past two 
years for the Soudan Railway, involving the use of 4160 

tons of steel, and ranging in spans from LOS ft. to 55 ft. 

The most prominent success of the Company's designs 
was in the International competition for the plans of 
three bridges over the River Nile at Cairo. 1 The firms 
participating in this competition were representative of 
the best bridge-builders in practically i'\cvv country in 
the world, and the Arm] design was accepted largely 
because of its merit, particularly in the details of founda- 
tion work, the symmetrical proportions of girders and 
fascia work, and the conformity of the decorative features 
with Egyptian art. The largest of these bridges, which 
are now in course of construction, is 1735 ft. long between 
abutments, in II spans, with ;. centre swing portion affording 
two clem- passages of 84 ft. in width for river traffic. 

There is another department of work to which we 
may now refer, namely, the construction of stations and 
workshops. In this branch of engineering the Company 
bave attained a success, alike in design and construction, 
as pronounced as in the case of bridges. 

The conditions in the workshops of this country have 

)een almost revolutionised by the construction of light 

^teel root-principals with extensive glazing. The first 

10of bmlt by the Company was that made in 1887 for 

See Engineerivi ,. 1 1 

Bering, vol. lxxv,,., page 682 j vol. Ixxxi., page II. 




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24 



I hi , n\-i ia CTION OF WORKSHOPS \\h 




the smithy of Dubs' Locomotive Works in Gla u. qqw 
owned by the North British Locomotive Company. Glazing 
was here introduced for the first time extensively, but 
the condition was insisted on thai the glass should be 
coloured, so as to subdue the sunlight. Since then opinion 
has greatly changed, and one <»f the mosl prominent 
instances of the extensive adoption of glazing is t<> be 
found in the root' of the new engine and boiler shops at 
the Naval Construction Works, at Dalmuir, of Messrs, 
William I>canlmore and Co., Ltd.. illustrated on page 23. 
The area of glazing is nearly :>', acres in extent. In the 
interval the Company have constructed a great number 
of factories and representative works. 

The illustration on page 25 shows the mot' made in 
1897 tor the Hon. <\ .\. Parsons' Works. This shop is 

<>t double interest, for. apart from tin' general success of 

the structure, it is the birthplace of the marine steam 
turbine: one of the most outstanding departures in engi- 
neering, which promises to revolutionise the propulsion of 
ships as well as the driving of electrical machinery. A 

list of the principal workshops erected is given in a subse- 
quent page. 

Amongst naval firms who have had buildings designed 
and constructed by the Company are Messrs. dickers Sons 
'»»" Maxim-; Sir W. ft Armstrong, Wbitworth and Co.: 
John Brown and Co.; William Beardmore and Co.; the 
T ' , ' ^Pbuilding and Engineering Company ; Cammell, 
a ™ and Ca; Setts' Shipbuilding and Engineering Com- 
P y » the Wallsend Slipway and Engineering Company; 
' ,ni1 Yarrow and Co. 

of Messrs f)T , "- 1 " e( ' n "."" h, ">* »ote may be made 

WiWcu ' aD and Co - of Glasgow; Ba brock and 

• Stewarts and Lloyds ; the Glenfield and Kennedy 








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NOTABLE CLIENTS KOK WORKSHOPS. 

Company Kilmarnock ; Marshall. Sons and Co., of Gains- 
borough, and others. The Charing Cross and City Electric 
Company of London, the Metropolitan Electric Company, 
and the Glasgow Corporation, are amongst the owners of 
electric power stations built by the Company; while 
there are such miscellaneous factories as Guinness 1 brewery 
at Dublin, a tannery at Canterbury, the Newburn Steel 
Works, Mc-Farlane, Lang and Co.'s biscuit factory, and 
H. and J. Templeton's carpet factory in Glasgow. 







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The 



Dalmarnock Works at Glasgow 



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The Dalmarnock Works at Glasgow. 



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TI1HK Dalmarnock Works of Sir William Arrol and Com- 
-*- pany, Limited, where the constructional steel work for 
bridges, workshops, railway and electric-power stations, 
and the like, is manufactured, cover an area of some 
17 acres, and the equipment includes many specially- 
designed machine tools. Here close upon 2000 men are 
employed ; but this does not represent the total number 
of the Company's employes, as on the sites where 
bridges, etc., are, from time to time, being erected there 
are large staffs of engineers and workmen, the total 
usually running into many thousands. We are here, 
however, concerned only with the organisation and equip- 
ment of the Glasgow establishment, and the influence 
these qualities have upon the accuracy, economy, and 
rapid production which are the desiderata in all factories. 
The principles winch are prominently kept in view- 
are ( 1 ) the adaptation of design, as far as possible, to 
suit special tools and systems of manufacture ; ( '2 ) the 
preparation of full and clear detail drawings for the 
shops ; and ( 3 ) the extensive use of templates for all 
units to ensure absolute precision. These result in the 
component parts being so accurate, when they enter the 
machine-shop and erecting departments, as to minimise 
time and trouble, and to eliminate the possibilities of 
error. In the appreciation of the great importance of 
attention to such preliminary detail in technical and 



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,,l \l i;\l. (VRRANGBMBN1 OP WORKS 



commercial matters one recognises the greal experience 
of the founder <>f the Works, sir William Arrol. and of 
his co-Directors, -Mr- A. S. Ui-^art, Mr. Thomas Arrol, 
and Mr. John Hunter. 

The Works include five erecting departments, besides 
the pattern, joinery, and template shops, which are common 
to all. Each of the five is independent, with its own 



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A Receiving Yard for Material. 



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nmin^' '" lfrK ""' '"''"""' '""' P late -straightening machines, 
m S and planing tools, drills, presses and riveters, so that 

,;' ''''"' ' ' ,k ' h ' gW" to conform to plan. The dew 

iir ' K B f Aow. the receiving yard for one of these 

byanoviTr^ [t is 122 ft. wide, and b tn sed 

teQtona rnead electric crane with a lifting capacity of 

<•'«• <i>i-it, ,' e , " ; "'" erectin S 8h °P is * iv "" "" 

As indicative ,»+* +1 

01 the sequence of operations and of 









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METHODICAL v i; ic \N«. BMBNT OF TOOLS. 

the methodical arrangement of tools, we produce on the 
opposite page a plan of the same machine and erecting 

department. The receiving department shown on page 30 is 
at one end. The angles and beams are discharged at A. and. 
when required, are passed to the straightening machines 
B and C, which are actuated by a 10 horse-power two- 
pole shunt-wound motor. In line with these are three 
saws marked D. K. and F, which cut the angles and 
beams to the required length. 

These are conveyed on wagons on a 2-t't gauge 
railway to the benches at the drilling-machines, where 
they are brought into contact with the cover, web and 
ether plates, to form girders or columns. The plates 
are discharged about the point marked L. and are 
flattened on the rolling-machine M, which takes plates up 
to 7 ft. in width. This tool is commanded by one of the 
many 3 -ton hydraulic jib-cranes installed throughout 
the Works. The plates are replaced on wagons on the 
narrow-gauge railway for conveyance to the edge-planing 
machines marked P. Q, It. :uu i <>. Thence they ,, 1SS t0 

the benches at the drilling-machines, to be fitted together, 

^•ordmo- to template, before being drilled. Having been 

" . ■ the y are Passed along the trolley lines to the 
erecting and riveting shop 

ere is thus no retrogressive movement, no unneces- 
sary nandhng or transit. To ensure these conditions, such 
JJ*m hydraulic angle-shears 

utilise"! aTtj£f le ? tiffener8 > 1'late-joggling p^s, etc, 
dotted ) , * eS ° f t,le l"-" wss of machining are 

^'luhed in thl t *' S ° that the ? st:,ml wheK 

towards the Progression of the component units 

assemblaee tofcTi? a " d rivetin « sho P- «'h*» the final 

ot! talve « place. 



presses for stamping knees, 




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HANDLING MATERIAL. 



Facility in handling is an equally important considera- 
tion in the economy of all works, and in the Dalmarnock 
establishment it has had adequate attention. Most of 
the views which we publish on succeeding pages indicate 
clearly that there is practically no square fool of work- 
shoD or erect intr yard which is not commanded bv 
hydraulic jib, or electric or steam travelling-cranes, and 
in must cases there are two. 

In the design of the L20 jib-cranes installed, the 
Company have profited by their extensive experience. 
Of the number, seventy-four are of the hydraulic type. 
These are. as a rule, of from two to three tons lifting 
capacity, with a range of vertical lift of 7 ft. The hoisting 
time when loaded is twenty seconds, and when unloaded 
twelve seconds. In manv eases the jibs describe a complete 
circle; in ethers the are has been arranged to suit the 
situation or requirements. In addition, there are seven 
fixed steam cranes ranging up to 15 tons capacity, and seven 
locomotive cranes of 5 tons lifting capacity working on the 
broad-gauge railway. Stain Ian I gauge and 2 ft. gauge 
railways arc laid throughout the works. 
_ _ Instead of describing the departments successively in 
'tmerary sequence, with their duplication of shops varyin 
only slightly i„ equipment and in the details of the 
machine tools, we propose to follow a typical production 
'™gh the various stages of manufacture, from its design 
» Jto completion. The processes differ little for all steel 

caUson f 7 th -' nlti " ,ate f ° rm is ;l S irder for a brid ^ e ' a 

for a w °k m " fouQd ations, a steel-framed structure 

ortsnop, station, or other building, framing for 

Giants, piers ov f ' 

other ,„„,.,•,, s "'! T 'I'l"' 1 ' or ™»'.» '">■ ■■'"' '"' 












DESIGNING AND DRAWING OFFICES. 



35 



The designs, whether by outside engineers or by the 
Company's staff, are passed into the Works Drawing Office 
illustrated on this page. This is a well-equipped depart- 
ment with about thirty draughtsmen : and here working 
drawings are prepared, the originals being subsequently 



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One of the Drawing Offices. 












catalogued, and arranged methodically in a large fireproof 

safe for future reference. As the Company are frequently 
called upon to alter or add to structures some years after 
they have been built, these stored drawings have proved 
vcrv useful. The drawings are "traced,"" and from the 
tracings there are made "sun-prints" in an extensive 
photographic department, and tiiese ultimately become the 
shop drawings. There are separate staffs for bridge work, 



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1*1 MAK1N-. OF UI'LAI 



constructional steel work, and for mechanical engii ering 
with designing offices for each. 

Prints and specifications are Issued to the template 
.hop. and to all the other departments concerned; nothing 
is left to the judgment of the worker; the rule is enforced 
that prescribed details shall be followed. In ch case 
exact dimensions are specified, with a note of the natui 
of the work t<> be performed on each unit, and an indi- 
cation of the marks which each must bear to facilitate 
erection on the site. 

The procedure in the template shop, where practical 
work begins, make- or mare the success of the job. The 
efficient realisation of the designer's ideas is dependent on 
the precision practised here. Accuracy also influences the 
economy and expedition with which work is subsequently 
accomplished. The methods followed at sir William Airo! 
and Company's Works are therefore interesting. Their main 
template shop, illustrated on the opposite page, is a large 
and well-light,., 1 loft, 310 ft. long and 42 ft wide, with an 
absolutely level and blackened floor, Ave from obstructions : 

the necessary w l-working machinery for making the 

templates, etc., is arranged in a separate shop the 

same floor. 

From the "sun-prints" the template makers draw 
t '<■ girder, or column, or other piece of work, to its full 
" ,me " slons "Pon the floor, giving, of course, any earn- that 
^J be specified. The templates are formed to the same sise, 
d ; « spngged down over the lines drawn on the floor. 
™*L units, which fit into or overlap each other in the 



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MACHINING BARS POR GIRDERS, 



The view on the preceding page of the template shop 
shows, built up oe the floor, the templates of a span and 
a -half of the girders of the 1 2 > of the three bride 
over the Nile at Cairo— 1735 ft. long. Thes gird* 
it will be seen, of the lattice type, and the length of 
irder in the illustration i> i irly :;<•<> ft. 



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Cutting Bars and Angle.- for Girders. 

With such templates, and the drawin s and s ecifi- 
rations, the constructors have a relatively simple task. 
"e bars to form the girders are flattened in bvdraulic 
JJ*™* and the pl ates are straightened in roll! The 

cut to the required length in hydraulic sh - 
t'T ° Ut,is I,: '-" : but where the ends are to but 
to ensure alneTed^T ' "" <" **"* *** "* ' "'" 

^ tt ^eoudy the plates have their edges ph. I 
•» several very heavy tools in the worl - 









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M M-IIIMNii I'l. VI ES Ki»i; i;i I." I»KI; v 



39 



this purpose. They are, as a rule, side and end machines, 
so that one side and an end may be planed simultaneously. 
Several of these tools thus work plates 36 ft. long and 
7 ft. wide. To expedite matters, the tools have in all 
cases hydraulically-ope rated jacks for holding down the 
plates on the tables. These fix the plates much quicker 




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Planing the Edges of Plates for Girders. 

than the old screw-down jacks. Two of these magnificenl 
tools are illustrated on this page. 

While this work is going forward, there is proceeding 
in one or other of the forges the stamping of knee-bars, 
curved or twisted bars, benl plates, and other small parts, 
to form stiffening pieces, connections, and other parts of 
girders. 

O m 

Formerly the cutting, setting, and welding of these units 
to the required form was done by hand, which entailed a 
large amount of labour by smiths. But special tools were 



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STAMPING K*H BARS LND OTHER SMALL I WITS OP GIRDERS. 

devised by the Company, by which each of these pieces-of 
great variety of shape and size— is formed at one or two 
operations, and with greater accuracy of dimension than by 
hand-work. Such a machine consists of an hydraulic cylinder 
mounted horizontally on a table. On the ram-head thei 
are mounted "former" blocks, while on the table in front 
there are secured corresponding dies. The red-ho1 bar is 

placed on the table between the blocks, and an hydraulic 

pressure of < s o<> lb- per square inch on the ram forms the 
bar between the blocks to the exact shape required. 

(hi the opposite page there are two engravings of 
this process, one view showing the straight red-hot bar 
placed in position, with many parts completed in the 
foreground; in the other illustration there are shown 
various forms of the dies used. Not only is the operation 
expeditiously executed, but there is no uncertainty of 
weld. The whole of the metal in the bar is retained in 

the inside of the knee, where it becomes thicker and 

broader, materially adding to its strength. 

While moulds or blocks can be made to suit any form. 
there is an advantage, in the designing of details of 
structures, in utilising existing specialised tools to the fullest 
extent. This is only one of many reasons which might 
be adduced in favour of the design of details being largely 
left to the manufacturer. 

m The web and cover plates, angles, knees, stitienin-- 
Pieces, etc.. thus separately prepared in tools adjacent bo 

"J °«ier, are conveyed to the table of a long battery of 

"J™ hl each of the yards there are such collections 

is .then, being about one hundred in the Works. On 

Tllt lustration on mir( > o, t] . . . , 

these drill ' there is shown a series of 

len-th h " 'V i tW ° 1Ws ' tlle tal,,(ls being of sufficient 
° t0 ***** "* long girders to be set out. and the 









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H\draulic Machine for forming Knee-Bars. etc. 







Machine and l>ies for I-orming Small Units of (iirders. 



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RADIAL DRILLS 



units built up in their relative positions. The vie^ on 
the opposite page shows another battery of drills, twenty- 
four in num ber 3 in two rows, to work trinUw up to 225 ft. 

in length at one setting. 

The templates are here brought together, and tin- metal 
parts take their allotted places, when all holes are marked 
off. The radial arms of the drills command the whole 

length and depth of the embryo girder as it lies horizontally 

on the bench. The arms are ;it 12 ft. \\ in. centres, and 
have a radius of 9 ft. 6 in. Spiral drills are used throughout; 
and as a consequence of careful tests of tool steel, the 
Company have been able to increase the speed of drilling 
to 250 revolutions per minute. Holes are sometimes drilled 
through twelve, fourteen, or even sixteen thicknesses of 
plates at one setting, and the heavies! of girders can be 

assembled and drilled in a few days. There are other 

benches with universal drills, for dealing with curved or 
varying forms of constructional steel work. 

Hydraulic jib, or overhead, cranes command the tallies. 
and the girders, bolted together in the case of small members, 
and in sections in case of large members, are taken on 
bogies on the 2-ft. gauge railway to the riveting depart- 
ment. Prior to being thus finished, tliev are thoroughly 
scraped, and oiled or painted. Another provision to obviate 
™st is that most of the work is carried out under cover. 
Alter the meeting surfaces have been painted or oiled. 
"' umta are rioted, the hydraulic machines for this 
P«P« being suspended on cranes. 

. e ^ ave already narrated the circumstances attending 
Kir ;; i .!' | '." l '"- (l "» <>f the hydraulic process of riveting by 

to l.Ji ''"'I , and Company, and of its superiority 
Z™*^ there is little ue0(1 liow to ^ [tggreat 

lat 't ensures an absolute contact at all points 






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f the riveted surfaces, and the perfect filling of the holes 
by the stem of the rivet. Samples of hydraulic rivel work, 
when sawn through on the centre line of the rivet, have 
Dot shown the slightesi interstice between plate and rivet 
There is little limit to the application of the hydraulic 
riveter, and the Cmnpniiy manufacture a great variety 
of forms and sizes suitable ' for almosl every type of 




Riveting:, 

* ork ' In instances where the jaws of the riveter cannot 
, | ' l i '; v "" l "" tl . v ""*, the pneumatic svstem is applied, 

SL25T! ,,;ls Qot sh — ■ " to "be s .nical. 

b ,^S ££ are als ° appUed for reamering and boring 

m,„.,l",n ''''."' 0ther P iece of constructional work, when 
painted ,V"j, , "" ''*''" be d '" th " Works ' is 

It is then loaded d-- '"'"''""' '"'' erectiou P ur P oses ' 
adjacent t,, t'i " ' ',"' f mto railw »y wagons on the sidings 

"" Works > and despatched. 



THE DECKING OF BRIDGES, 



15 



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S 



Special tools have been devised and manufactured a1 
the works for forming plates of various shapes, such as 
are used now for the decking of bridges -trough, buckle, 
or curve plates. These are worked to shape in hydraulic 
presses of great power. Former dies — flat, dished, angular, 
or circular — are secured, one set on the underside of the 



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Large Press for Forming: Plates of Various Shapes. 

entablature or head-piece, and the other corresponding set 
on ;i table secured on the top of the ram-heads on one 
or more cylinders. A large tool of this type is illustrated 
on this page. 

Near to the end of the press there is a large furnace, in 
which the plate is brought to a red-heat, and from which 
it is afn-rwards withdrawn by hydraulic power on to the 
table on the ram-heads. The plate is held in place over the 

dies, and by the working of the hydraulic cylinders is 



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I ussONS FOR POUND \ PIONS OF BRJDG1 



forced upwards into contact with the corresponding former 
dies on the underside of the headpiece. As the pressure 
reaches 1000 tons the plate assumes the shape aimed at, 
and is ultimately pulled from under the press by hydraulic 
jiggers, being left on skids to cool and to be prepared 
for further operations. The press illustrated deals, al one 
operation, with plates 30 ft. long and 6 ft. wide, and has 
proved a most efficient tool. The same press is utilised 
for flanging work. V's being then used instead of die-stamps. 
There are also hydraulic joggling machines and other 
presses of a kindred nature for various operations. 

An important department of the Company's steel work 
is the making of heavy caissons for the foundations of bridge 
piers, quay walls, etc. These Conn the working chamhers for 
excavations under air-pressure. To facilitate the sinking 
of a caisson it 1ms a cutting edge at the bottom : so that 
as the excavation proceeds and weight is added from above, 
the caisson, which ultimately forms the base of the pier, finds 
its level on the mek or firm foundation. It is ultimately 
''"'•'I with cement concrete. This was the procedure at the 
Forth Bridge, where the an,, of the sub-aqueous chamhers 
under pneumatic pressure was exceptionally large, being 
< tt in diameter. As we have already indicated in the 
Previous Chapter, great depths have been reached in the 
£W* operations in the ease of the foundations for 
^s, ,n,l the firm have thus accumulated considerable 
J*J«a acquired unique experience as to the details 

thenW- '?., appl,cation Of compressed-air caissons, and 
"» Plant incidental to such work. 

and ah ti'w • Iwig , ' e,, °-" ise d the importance of water- 

"■y <-<-iinnr°" s ' and because of thi « the y have had 

*™-'» of sink SUCCeSS iM deep *»»W*m *ork. This 

lg Is " ot 0,ll y expeditious, but brings the 




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BUILDING A SCHERZER ROLLER MFT span*. 



47 






jreater surety which comes with the possibility of a thorough 
examination of the whole surface of the foundation. 

The Company also manufacture the machinery con- 
nected with the pneumatic sinking of such foundations, 
including the a i r-compressors, reservoirs, locks, etc., as well 
as jacks and other hydraulic appliances for lowering the 
caisson into position. Their twenty years' varied experience 




Building a Scherzer Roller Lift Span. 

has resulted in many improvements in the details and design 
of such mechanism. 

Many of the bridges built by the Company have 
opening spans of the swing or rotating type, of the bascule 
system, and of the newer Scherzer roller-lift design, and 
to the most representative types we have referred at 
some length in the preceding Chapter. 

The engraving on this page shows one of the erecting 
yards, where a Scherzer roller-lift span is being constructed 



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, A( .|\i ERIKO DEPAR1 WENT. 



fol . tlir Ross lare and Waterford Raiiwaj Bridge over the 
River Suir. The span in this case is 50 ft., bul eight 
fix ed spans make the total length of the bridge L 205 ft 

P or a n types of opening spans the Company construcl 
the actuating gear, whether the motive power be steam, 
hydraulic or electric, and for this and other engineering 



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Erecting Shop in the Kngineering Department. 

work a separate department is arranged. There are also 
, " : " 1 " here all types of hydraulic riveters and presses, 
'':"""". Unls[s - etc. : special machine tools, prime movers 
"' various kinds. coa ] elevators and conveyors, and the 
gas retort charging and discharging machinery now so 
extensively adopted. 

cm 

fte engineering departmenl includes a machine-shop 

widtl - °^f "'"' '"' S "■ wi,k ' T1 "' main l,;,v - 50 '''• i " 
'• ls "histrated on this page. It is reserved for the 










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IIH , ENGINEERING Dl PARTMI M 



•ecting work, and the overhead traveller is of 35 tons 

The central bay is .*><> ft. wide, and the third 



capacitj 



bay 48 ft. 

It is scarcely necessary to describe in detail the 

various machine tools in the engineering shops. Many 
of them are of a special type for carrying out unusual 
operations. There is. for instance, a milling machine, with 
a special radial attachment for facing up the ends of steel- 
built columns and girders after the riveting is completed, 
so as to secure absolutely true bearing surfaces. This tool is 
particularly useful in connection with the construction of 
large rolliner-lift or swing 1 bridges. On a planing machine, 
again, there is an attachment for dealing with the bevelled 
faces of ndlcr-paths of revolving swing bridges. 

The brass-finishing department has a splendid equip- 
ment of automatic and other machine tools, and a view 

of it is given on the preceding page. 

There is in connection with this department a brass- 
foundry and a well-equipped tool-room. The system of 
jigs and gauges is most complete, so that all parts are 
made interchangeable, and repeat orders can at once he 

met. In the smithy there are twenty-five hearths, five 

miners, and three hydraulic presses. 
The power plant for the whole of the works is con- 
centrated at the Central Station, which is modern in its 
W^ent, and has. i„ addition to electric Generators. 

^aulic pumps with accumulators, air-compressors with 
Reivers, and other accessories. This station is illustrated 
1,11 Pages 51 and 53. 

f he main steam p l ant consists of a range of Babcock 
Ucox water-tui* boilers, suitable for working at 

• a ue steam is superheated to the extent ot 



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NIK POWER STATION. 



51 









LOO deg. Fahr. The Company have installed their own 

system of coal-elevating' and conveying plant, and with it 
they have made experiments and evolved improvements 
for the corresponding appliances which they manufacture 
for clients. The arrangement of the plant is shewn on 
the plan on page 33. The coal is brought by railway 
trucks into the siding, and there are two hydraulic wagon- 




View in Power Station. 



tipping cylinders for discharging the contents into a hopper, 
whence the fuel falls into the boot of a bucket elevator, 
which passes it into another hopper. Thence it is taken 
by an overhead conveyor, with weighing appliances, to be 
discharged into the runway across the front of the boilers. 
From these it is finally fed into the boilers by automatic 
chain-grate stokers. The system thus obviates all manual 
la hour. 

There is a Corliss compound engine of 2(H) horse- power 
for driving the shafting in connection with the Large tools 






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BL3ECTRK M- DRIVING \M» LIGHTING. 



. line wit h the power station. With tliis exceptioD all 
Lchines are operated by power transmitted electrically. 

The chief electric generating set consists of a 
630 indicated horse-power triple-expansion engine, coupled 
direct to an er-ht - pole compound - wound generator of 
400-kilowatt capacity, which gives current for both lighting 
and power. There is also a 250 horse-power compound 
engine, coupled direct to a four-pole compound -wound 
generator of L50-kilowatt capacity. A third dynamo of 
70-watts capacity is belt-driven from the Corliss engine. 
The total capacity of the generators is therefore 620 kilo- 
watts. The electric cables from the dynamos to the main 
switchboard are taken along underground channels entirely 

separate from the steam exhaust pipes. 

The current is transmitted from the main switchboard 
by heavy feeder cables overhead, distribution boards being 
situated at convenient points in the works. 

A word mav he said about the system of driving. The 
motors, almost without exception, arc of the 4-pole shunt- 
wound type, and while many are independently connected to 
cue machine tool, others work lines of shafting from which the 
tools are belt-driven. Tims, in the engineering shop, where 
the current is controlled from oik- distribution board, the 
principal lines of shafting are driven by four semi-enclosed 
30 brake horse-power motors, running'at 560 revolutions 
per minute. The large overhead cranes have independent 
motors for hoisting, travelling, and cross-traverse, the con- 
rollers in all cases being of the tramway type. In the 
girder -erecting department, the two Latteries of radial 
' ' aiustra ted on page 31, are each run by a 50 horse- 

power lnnrm- o 1 . , J o 

sdm . 1 U1 ' a ^-straightening machine by a motor of 

^miliar nmvm- • ,.i 'i J i 

1 ' • wiule m the girder-erecting shop, illustrated 
v* M, there are three l()-ton and one 20-ton overhead 



on 









ELECTRICAL MIMVIXc AND I l<:i[TI\<:. 



53 



travellers, each having three motors ranging from 5 to 
25 horse-power for hoisting, longitudinal travel, and cross- 
traverse respectively. The Roots blower in the smithy has 

a 10 brake horse-power motor. 

As regards lighting, there are 150 are lamps, and with 
a few exceptions these run five in series on a 250- volt 




Hydraulic Engines in Power Station. 

circuit. All the constructional steel departments are lighted 
by 10-ampere are lamps of the open type. The drawing 
and tracing offices are lighted by ten inverted are lamps, 
while the commercial offices have incandescent lamps of 
32- and 16-candle power. In order that the offices may be 
illuminated while the works and power station are closed 
down, 137 Storage cells are provided. The template and 
pattern shops, where there is danger of lire, are lighted 






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II vim; \nn' POWER 



both by enclosed arcs and incandescent lamps. Ami here 
it may be said that very special precautions have been 
taken against outbreak of fire. One interesting feature of 
the electric equipment is the installation, in different parts 

of the works, of fifteen clocks on the Becker. Barr and Stroud 
system so that workmen can always ascertain the time. 

Hydraulic power is used extensively in the works. 

There are installed in the power station two of the Com- 
pany's compound pumping engines. One of these is seen 
in the forefront of the illustration on page 53. The two 
engines differ slightly in dimensions, but they each deliver 
about I:2.<)iiii gallons per hour nt a pressure of about 900 lbs. 
per si | uai-e inch. The cylinders are of the tandem type. 
The power water is delivered into an accumulator, IS in. 
in diameter by 14 ft. stroke, placed outside of the engine- 
room. This accumulator regulates the steam admission to 
the pumping-engines in the usual manner. The power 
water for the hydraulic apparatus is distributed throughout 
the works in a 4-in. cast iron main, laid 4 ft. under the 
ground level, so as to obviate any interference by frost. 
Branch pipes are laid to the various shops and tools. 

From what we have written regarding machine tools 
it will be noted that hydraulic power is used for cranes, 
meters, presses, lifts, and jacks for planing machines, etc. 

"' return ex haust water passes to an underground tank 
about .50 It. long, whence it Hows to the supply tank for 

'" e ngme. This latter tank, placed contiguous to the 
'»<»" pumps, is connected with the water from the Glasgow 
^'•I'orauon gravitation supply, so that from time to time 
* h€ ?f a P "' «* astern may be made up. 

- n air-comp.vssing plant is also accommodated in the 

- tat,,.,, consisting of , triple-expansion engine, 

aar - ^Pressors capable of delivering 1000 ft of 






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[NFLUENCE OP EXPERIENCE 



free air per minute at a pressure of LOO lb. per square 
inch. The steam cylinders are placed over the air- 
cylinders, as is now almost universally the ease, and the air 

is delivered into a receiver adjacent to the compressor; 
thence it is distributed throughout the works in 4-in. 
mains, with small branches. The compressed air is used for 
working drilling, chipping, caulking, and riveting machines. 
It will thus be seen that, from first to last, the organi- 
sation and equipment of the establishment have been 
developed on most efficient lines, arrived at by wide experi- 
ence; and that a strictly progressive policy has been pursued, 
especially where carefully-conducted tests proved that a 
newer appliance would ensure greater accuracy and facilitate 
work. These 1 two advantages carry with them the further 
benefit of economy. 



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BRIDGE BUILDING. 



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A Retrospect. 

THHE beginning of the industry of bridge building may 
almost be said to belong to prehistoric times. 
Certainly, in the work of the ancients one finds crude 
but suggestive applications of almost every principle 
embodied in the design of modern bridges, including the 
cantilever, the suspension, and the compression parallel 
girder systems. If the aboriginal was not versed in the 
principles of stresses and their resulting strains, he never- 
theless produced useful structures within the limitations 
of the materials and constructional appliances available. 

Wooden bridges are, of course, of greatest antiquity, 
and although masonry was sometimes employed, timber 
was used almost exclusively until the nineteenth century. 
Many long spans were built of timber prior to that period. 
Outstanding examples are the Wittingen Bridge, with a 
span of 390 ft., built in 1758, and destroyed by tire at 
the beginning of the nineteenth century ; Hanover Bridge, 
over the Connecticut River, in the United States, with 
an arch of 236 ft., built in 1796 ; and the Schaffhausen 
Bridge, across the Rhine, of 193-ft. span, destroyed in 1799. 
The longest timber span in Britain is probably the Landore 
Viaduct, in Wales, with a centre span of 107 ft., of which 
an elevation is reproduced on the next page. 

Masonry was adopted more largely by the Romans. 
Grecians, and Egyptians ; but even in modern times the 
maximum span possible with stone arches is comparatively 



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60 



HISTORICAL HASONR1 BRIDGES. 



small. The 250-ft. span of the Tezzo Bridge, over the 
Adda, is, perhaps, the greatest ; and amongst other aotable 

examples are the 220-ft. span of the Cabin John Bridge, 
Washington Aqueduct, the 200-ft span of the Groa enor 
Bridge, over the River Dee. at Chester, the 152-ft. span of 



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MAIN SPAN (107 FEET) OF LANDORE VIADUCT 
LARGEST TIMBER SPAN IN BRITAIN. 




p'-'' 1 "" P> "^'' aud the 141 i-t't. concrete span of the Alma 

and its ' 1 re ls n,u, "'> to commend masonry, 

' * Popularity has continued for moderate spans, 

PW ^ in combination with iron or steel ribs, 
cast-iron ,,'t ,""' ta ' b " dge V;|S constructed in 1779— a 

— o EST" f°V"" ft -""- " ie Riv '"' Sm ' n " 

' * Growing m quick succession were 



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EARLY METAL BRIDGKs. 



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several others, including a cast-iron bridge over the River 
Wear, at Sunderland, built in 1796, with a single arch 
of 236-ft. span. The Southwark Bridge, with a central 
span of 240 ft., was built in 1819. These metal bridges 
proved cheaper than masonry or wooden structures ; but, 
because cast iron was considered suitable onlv for com- 
pressive strains, it could not be used for girders ; the 
stone arch was still accepted for most purposes. 




First Iron Bridge ever Erected. 

By the perfection of the principle of the suspension 
bridge it was found convenient to utilise the tensile, as 
well as the compressive, properties of metal. AMrile 
one or two small examples date from the eighteenth 
century, the first notable erection was the Union Bridge, 
over the River Tweed, with a span of 449 ft., completed 
in 1820. Then followed, in 1826, the opening of Telford's 
beautiful structure of 570-ft. span across the Menai Straits, 
102 ft. above sea level, and another at Conway of 327-ft. 
span. The Freiberg Bridge, over the Sarine Valley, in 



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62 



SUS PBNSIOM BRIDGES AND I'HEIB LIMITATIONS. 



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Switzerland, erected in 1833-34, was of 870-ft. span, 

and 169 ft. above Mater level. The Buda-Pesth Brid« 
over the Danube, of 660-ft. Bpan, was built in 1842-49. 
The Clifton Bridge, over the Avon, erected in 1862-64, 
had a span of 702 ft., and was 250 ft. above water 

level. 

Among the more notable modern examples of the 

suspension system are the Niagara Bridge of 821-ft. span; 
the Brooklyn Bridge, with a central span of 15!).5 ft.; and 
the new Williamsburg Bridge, also across the East River 
at New York, of 1600-fb. span — the largest suspension 
bridge completed. 

The railway era brought new problems for the bridge 
designer. To the carrying of a dead load there were 
added all the difficulties of providing for a live or rolling 
load, associated in many cases with the necessity for 
providing considerable head - room beneath the bridge. 
The arch met the former condition, but limited the 

head-room; while the suspension bridge, although affording 
the necessary height, did not give the desired' rigidity for 
the hve load. Again the model of the ancients inspired 
■ugiiieers towards the introduction of parallel girders, with 
™ ^ ie,,ll **s, to take the place of the timber beams. 
»<? first of such girder bridges for railways was that 
completed in 1843 on the Dublin and Drogheda line-a 
awice iron structure, in imitation of wooden bridges built 
iL' TT U ' Smee then we hav e had many variations 

ii Oiii Robert si+^^i 

th* p u . ,Me ! jhe "* » 's rectangular tubular structure- 
anu tu ,"" Bl ' i<lge> WH] ' two ce ^raJ spans of 459 ft.. 
with a iT 8pan8 ° f 23 ° ft - •««« tl'o Menai Straits. 

This w ' T « tXy ° f m * ft - abov e high-water level. 
lu *a was the tirwt Ki.:j , 

But steel of , ^ e "'^e entirely of wrought iron. 

mUch h *8hw ductility soon displaced the 



. 















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. 



THE MODERN PARALLEL GIRDER BRIDGE. 



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wrought iron, and now every conceivable form of girder 
has been applied. 

The aim of the succeeding pages is to deal with 
modern types, and with the introduction of various 
mechanisms for opening spans to pass river traffic. No 
apology need be made for accepting the work of 
Sir William Arrol and Company, Limited, as typical 
of modern bridge engineering, since they were not only 
responsible for the construction of many of the most 
prominent bridges, according to the designs prepared by 
the most famous British engineers, but have themselves 
in recent times done valuable work towards simplifying 
design and economising construction. The story of the 
building of some of the greatest of these structures 
constitutes a record of ingenuity and skill which is a 
credit to British engineering, and to such work of erection 
special reference will be made. 

On the two following pages there is a list of the 
principal bridges built ; and in the Appendix a standard 
specification, which the Company have prepared as the 
result of their extensive experience, and certain formuhe 
and data of interest to those engaged in the design 
of bridge and structural work generally. 



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The Forth Bridge. 

THE Forth Bridge, 1 probably the most famous, and 
certainly the largest, of all railway structures 
is the most notable exemplification of the ntilever 

principle. 

The idea of bridging the Firth of Forth was suggested 

nearly two centuries ago. Early in the last century the 
boring of tunnels under the estuary was prop - d. But it 
was not until 1873 that a definite scheme was submitted 
to Parliament, with the view of connecting Edinburgh 
with the rich mineral and agricultural area north of the 
Firth. The proposal was favoured, because it obviated a 
long detour westward, via the Alloa and Stirlii _ bridg - 
across the river. It is true that there was a train-trans- 
porting ferry across the Firth at Burntisland, but this 
communication was intermittent The \^7'A --heme was 
for a suspension bridge, but for various reasons it was 
never carried out. 

The present structure ow^ its conception to the 
genius of the late Sir John Fowler. Bart., and of Sir 
^jamin Baker, K.C.R.. K.C.M.G., F.R.s. ; and as soon 
as Parliament, in 1882, authorised the carrying out of 
*e design, a contract was signed, and the work of 
•nstruction, under si, William Arrol's direction, was 
commenced in December of the same year. The desi- 
™J m ,Ul ~ 11 and construction were (1 rigidity, 
remcaU y ^der a moving load, and laterally under wind 



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TH 1 pRIKCIPAL DIMENSIONS, 




pressure: r2 l facility and security in constructioD to 
secure immunity from accident at any stage of rection; 

(3) the use of material proved by long experience; and 

(4) economy consisted with the fulfilment of the pre- 
ceding conditions. 

i 

The water-way at the site of the bridge is 5700 ft. 
wide, but the total length of the bridge is 8295 ft. 9| in., 
us approaches on a rising gradient had to be con- 
structed to ensure a height of <|iiite !•"><) ft. above high- 
water level in the centre, for the passage of steamers and 
sailing ships. 

The main feature of the structure is the three double 
cantilevers, with two intervening centre girders. The 
total length covered by the cantilever structures, with 
their connecting girders and piers, is 5349 ft. (> in. The 
Smith approach viaduct, with ten spans and four arches, 
accounts, with abutments, for L978 ft. : and the North 
approach viaduct, with rive spans and three arches, simi- 
larly makes up 968 ft. ;)', in. 

The site was selected partly because the island reek 
of Inchgarvie formed a natural hase for the construction 
»f the central pier of the bridge, as shown in the 
engraving on page 67. The two other piers, on the Fife 

extensive 

,. . . - — «~ c.,^. „,u caissons for the 

foundations. 

Resting upon independent piers, formed of iron, con- 
Jr an f M mas oary. great vertical steel columns, tour for 
;.J^a„ t , ever. riae to a height of 361 ft. above high- 

>.H,„i,,r ,f a t i! c ' any , t,K ' i2 " ft - t,,,,es formin s the ,naiu 

and.li,,. ., Cill,tllevt ' 1 - brackets, with their vertical 

11111 <uagona] bracimr tk • , i 

te river P1CTS Wt ' re 8Unk illto fche ' 

a depth, i„ , Suule vases of 5Q ft ;iml 00 ft 



and Queensfeny shores respectively, necessitated 
work m sinking into the bed of the river caisso 



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FORMING I II K I" 1 SDATIONS. 



to ensure a firm foundation, and were of sufficient area 
fco limit the pressure to about 5.1 tons per square foot 

under the dead and live loads, and a wind pressure of 

56 lb. per square foot. 

The caissons, which at their base have a diameter of 
70 ft., were constructed on shore, of plates, stiffening 
angles, and beams; and. when of sufficient height, were 
launched into the Firth ; and. weighing in some cases .ion 
tons and drawing 101 ft. of water, were towed to the 
point where they were to be sunk. A platform was 
formed on top to carry air-locks, cranes, workshops, etc. 
When these were arranged, the process of sinking the 
caissons through the muddy silt or (day was proceeded 
with. 

The construction of the caisson — probably the largest 
so far sunk under compressed air — is well shown on the 
opposite page. When the caisson had been sunk into 
the bed of the estuary, air pressure was introduced into 
the working chamber at the base, and the water and 
silt within it were ejected through pipes with outlets 
above high-water level. Workmen were then able to enter 
the chamber for the excavation of the heavier material, so 
that the caisson could sink into its permanent position. 
When the hard boulder clay was reached, it was found 
t, » be so dense and tenacious that only slow progress 
^d b e ]lmde 1)v p . ck ^ ^^ si ; Willia]n AlT0 , 

, "7 , d a tc>o1 which ' wl »te * i-ould be moved 

is on V^ UeVertheless grated by power; and as it 
ot many similar instances of invention, this tool 
lua > be bn efly described. 

a ^Zg"Z\ hydmUliC Spad6 ' havklff a ram ' t0 Whi0b 

le hydraulic cylinder which represented the 



fitteTbto T lifting 8Urfece WM attached - 



The ram 












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Section of Caisson with Air Locks and Working; Chamber* 



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72 



BUILDING Tin I'llliv 



handle of the spade. On the cylinder top there was a 
headpiece, which was set against the roof of the working 
chamber, and with this mechanism it was easj to deal 

with the hardest clay. From 6000 to 7000 cubic yards 
of material were excavated, the caissons being sunk for 
about 20 ft. into tenacious material. 

The time occupied in the sinking of each caisson 
averaged about three months, and in this period the 
immense cylinder was sunk to from 70 ft. to 90 ft. below 
high-water level. Two weeks sufficed for the filling in 
of the working chamber with concrete, where such was 
adopted. The upper part of each pier was built of masonry 
with rubble filling, temporary caissons being erected to 
exclude the water. And thus, practically hidden away 
from any view of the structure, there are. in the twelve 
piers constituting the supports of the steel superstructure, 
over 500 tons of steel. 2600 tons of iron, 44,000 cubic 
yards of cement concrete, and over 176,000 cubic feet of 
granite, etc. 

The time taken for the completion of each pier, which 
represented a weight of about 21,000 tons, averaged about 
fifteen months. The superstructure was of coursed granite, 
with hearting of Arbroath rubble. 

On the four piers were erected steel tubular uprigliK 
*w ft. high, to cany, from their base the main tubular 
members of each great cantilever arm, and from the top 
* braced upper members and diagonal ties. Tubes were 
Purred, because experience showed that this section gave 
S er resistance to compression stresses, weight lor weight, 

til, in other form* Ti, i ^ , • 

elevatioi ■ " columns are vertical only m 

abQ ' ™ . m>SS 8ecti <* thev have an inclination of 

at the L Tr ng u 120ftapart atthe bottom, and 33 ft. 

l- Ains batter is maintained throughout the 


































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Fife Pier Erected to Full Height. 







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0ONSTR1 CTING I II K i INTILB1 BUS. 



\VAHV 77. 



Thole length of the bridge, as shown in the engraving on 

The four columns, each rising from a separate 
masonry pier, arc thoroughly braced laterally and diagonally, 
forming a tower of immense strength and weight— 7036 
tons in the case of that built on Inchgarvie, and 4815 tons 
in each of the others — well able to resist the enormous 
stresses resulting from the combined influences of dead 
load, live load, and wind pressure upon the tower itself 
and upon the cantilevers projecting from it. 

All these stresses arc concentrated on the circular 

masonry piers, immediately over which are the main 
junctions or skewbacks. These are the gathering-points 
of live tubular and five lattice-girders of immense strength. 
Each column terminates at the foot in a flat plate forming 
the main bed-plate, which rests upon or slides along 
another, a lower, bed-plate, 37 ft. long and 17 ft. wide, 
fixed on the masonry pier. Only one skewback out of 
the four comprised in each tower is fixed : the other 

three, being free to slide, yield to the influence of tempera- 
ture and of lateral deflections produced in the cantilevers 
by wind pressure. Provision is also made at four points 
m the length of the bridge, at rail level, for temperature 
and deflection movements. 

The work of building the cantilever arms commenced 

of the 
member is 

— 1 ..._ _ ^nction to 

»'"'' being a straight Line, and passing into the next 
1 ion_ at an angle. These tubes decrease in diameter 



Ui "win-ling the cantilever arms con 
simultaneously from the top and bottom of each 
''.'"'/'Pn.ulits of each tower. The bottom me: 

|"™ '" "' . eross s <*tion, each portion from June 
.unction „. mo. « ~«._ . , . ,. J 



th)ln |o , toC * inese tubes decrease in diametei 

t. at the skewback to <>» ft. at the end of the 

10111 tn panel, aft " " 

top member, being always in tension, is 



i " v ' 1 »^ u 2 IU. (U I lie 

»" fona The WWcb they - Tad,mll .v become rectangular 

• ■ 

' »'• etween the two there °are diagonal struts and 









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EFFICIEN* \ OF C0NSTR1 OTIOW PLANT. 



ties, while in the cross section there are corresponding 
diagonals between the struts. 

The internal viaduct, which carries the permanent way 
for a double line of rails and a footpath on each sidi 
consists, in the main, of two lattice-girders set at 16 ft. 
centres, and of depths varying according to the length of 
the span. This internal viaduct is carried by transverse 
olate girders between the vertical columns of the piers, 
and bv vertical supports extending upwards from the point 
of intersection <>t* the vertical wind-bracing, between the 
main booms of the cantilever brackets. 

The erection of the superstructure, involving the use 

of 51.0(H) tens of steel, within three vears was a remark- 

■ 

able performance. Two thousand tons of steel were worked 

into the structure during some of the months. 

Such a performance is proof of the foresight of the 
contractors, and the efficiency of their management and 
of the plant they devised. It would be impossible, in the 
amount of space we are able to devote to this one bridge, 
to describe any of the tools invented by the firm to 
achieve their object. The immense tubes of the structure 
required special drilling machines and plate-edge planers; 
while in the work of erection the problems associated 
with the Lifting platforms, the securing of stages, the 
suspension of hydraulic tube-riveting machines and other 
tools, were scarcely less important than those associated 
with the design of the structure. The work of riveting 

was itself an important matter, and for closing the H 

; il,ll .'">' "veto used, a great variety of machines had 
C m f° du <*d to suit difficult positions. 

viaduet^'nT!. "** * "" "SK*"* the W 10 "* 
• mat from the south is well illustrated on the 

"* *' Page. 1„ this ease there are ten spans of 168 ft. 



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TRAFFIC OVBB THE BRIDG1 



each, four arches of 66 ft. each, and abutments 34 ft. 
wide- while on the north approach viaduct there are Eve 
spans of 168 ft., three arches of various sizes, with 
abutments 14 ft. 3A in. wide. The immense granite piers 
carrying' the girders to form the viaducts have each a has,. 
61 ft. by 31 ft., and are built solid, forming very handsome 
structures, suggestive of great strength. The abutment 
has a base of 108 ft. by 57 ft. Between the anchorages 
for the shore cantilevers there is. for the passage of trains, 
an archway, 24 ft. wide. 

In the bridge, with approaches, there were used 
51,000 tons of steel work, 65. 000 cubic yards of cement 
concrete, 49,000 cubic yards of rubble, and 750,000 cubic 
feet of granite. 

The bridge, which was completed in the earlv days 
of 1890, and opened by Ins Majesty the King, then Prince 
of Wales, on March 4, 1890, occupied in its construction 
seven years, and the cost worked out at £3,000.000. Over 
it there pass per day, on an average. 221 trains. 161 being 
passenger and 60 goods trains: and the joint owners— 
the North British, the Midland, the North-Eastern, and 
the Great Northern Railway Companies— have every reason 
to be proud of their enterprise. 









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The Tay Bridge. 



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mHE idea of bridging the Firth of Tay first took form 
-■■ in 1849, but it was not until 1870 that a Bill 
authorising the project was passed by Parliament, and 
the first bridge, 10,700 ft. long, was opened for traffic in 
1878. On the 28th of December of the following year, 
the thirteen central spans, each of 245 ft. and with a 
clear height above high- water level of 88 ft., collapsed 
during a violent gale. 

The utility of such a bridge, however, had been clearly 
demonstrated, and a new engineer, Mr. W. H. Barlow, 
and new constructors, Sir William Arrol and Company, 
Limited, were chosen for the new bridge. Its construction 
was authorised by Parliament in 1880, was commenced 
in June, 1882, and completed in 1887. It is 10,711 ft. 
long, with a width on top of 24 ft., to accommodate two 
lines of railway. 1 

The features which excited most interest in the new 
structure were the foundations and the wind-bracing, and 
severe gales have proved their efficiency. Public confi- 
dence, shaken by the collapse of the first bridge, has long 
since been restored. This is proved by the fact that whereas 
in 1889 the greatest number of trains crossing in a day 
was 104, the average is now 163, of which 119 are 
passenger and 44 goods trains. 

1 See Enuixeeiung, vol. xxxii., page 575 ; vol. xxxix., page 689 ; vol. xlii., 
page 604: "The X«*w Tay Bridge,'" by Crawford Harlow, B.A., M. Inst. C.E. 



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EVOLUTION OF APPLIANCES IND PLANT. 




Prior to the opening of the bridge, the North British 
Railway Company paid each year to the Caledonian Com- 
pany, for conveying through traffic over their line vid Perth, 
a sum equal to 5 per cent, on the cost of the new bridge 

The southern approach consists of three brick arches, 
with a fourth of exceptional dimensions to form the main 
abutment. For the northern approach there are eight 
spans, six on the foreshore between high and low-water 
marks, and two on land. Three are arches, and the others 
are built up of girders, resting on east-iron columns, 
with granite and brickwork pedestals. 

The bridge across the Firth has 74 spans: 13 over 
the central channel, with 24 to the north, and 1)7 to the 
south, shores. The permanent way is carried on the top 
of the girders in the case of the northern and southern 
spans, which vary from 56 ft. to lis ft., but it is on the 
bottom booms in the case of the central spans. This 
ensures a clear headway of 71) ft. for the passage of ships. 
Eleven of the central spans are 245 ft., and two are 227ft. 

In the evolving of appliances and plant for the 
execution of the work great ingenuity was exercised in 
this, as in other large undertakings carried out by sir William 
Arrol and Company. This care and foresight contributed 
largely to the economy and rapidity of construction, as 
well as to the efficiency of the completed structure. The 
story () f the building of the bridge is, therefore, of interest. 

The piers, which cost £4000 each, are founded 20 ft. 



»■;* the bo,l of the Firth, to provide, amongst other things, 
anist scouring action. The base is proportioned to limit 
B load to :u tons p^. S(|Uaiv foot . {]w tegt _ a dead _l oa d 

™? exactly double this. Each pier consists of two iron 
" bgWater ^ by a horizontal east-iron rider 8 ft 










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Till PIERS, 




deep, or, as in the larger piers, by smaller cast-irm, girders, 
covered with masonry and brickwork. These transverse 
girders have a width corresponding to the diameter of the 
cylinders. This arrangement increases resistance to the 
action of floods and floating masses. From this level the 
piers are octagonal shafts built up of wrought-iron plates, 
angles, and tee-bars, with internal diaphragm plates at 
short intervals in the height. These shafts are united at 

the top by the semicircular arch on which the main girders 
of the bridge rest. The arches distribute equally the dead 

and live loads and lateral stresses, which are transmitted 

through the cylinders to the foundations. 

The sinking of the foundations was carried out with 
expedition and security. On the site of each pier there 
was formed, as described on page 10, a working platform 
on a pontoon, so arranged as to leave vacant the water 
area through which the two cylinders were to be sunk. 
Successive lengths of each cylinder were constructed on 
shore, and conveyed in barges to the pontoon, on to 
which they were lifted by cranes to be subsequently 
lowered into position by hydraulic gear. As soon as a 
cylinder touched the bottom, grab dredges were used to 

excavate the material in the interior. When- necessary 
it was loosened by hydraulic jets, acting at the cutting 
edge, and manipulated by divers. The cylinders were forced 
downwards, partly by superimposed weights, and partly 

>y hydraulic jacks mounted on the pontoon. The pontoon 
was kept rigid by its connections with anchoring legs which 

'•"' >>een driven into the bed of the Firth. In these 
'"' Were holes f <» the insertion of pins, to serine the 
Pontoon at a level coincident with the height of the 
cylinder work. 

When the cylinders had been sunk to the required 















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Transferring Girders from Old to New Piers, 



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TRANSFERRING GIRDERS FROM OLD PO \KW PlBRg. 



depth they were filled with concrete, packed, where acces- 
sary, by divers. Tlie girders connecting the two cylinders 
of each pier just above high-water level are enclosed in 
brickwork. Above this level are the octagonal shafts, with 
a connecting arch transverse to the line of the bridge at 
the top. The wrought iron plates, angles, tee-bars, and 
diaphragm plates forming these shafts were made to 
template at the Glasgow Works of the Company, and 
brought to the site ready for erection and riveting. The 
piers are illustrated on the preceding page. 

It was decided to use many of the girders of the 
old bridge, which was 60 ft. distant from the new struc- 
ture. For transferring these girders from the old to the 
new piers, pontoons were constructed with a platform on 
telescopic supports, so that tlie height could be varied to 
suit the level of the bearings for the girders. Tlie pontoon 
was moored under an old span at low water, and. floating 
on the rising tide, it lifted the span, which was then 

conveyed between the new piers, and lowered by hydraulic 
jacks into its new position. 

The new bridge lias two railway tracks, the old bridge 
had only one. Four parallel lines of girders were therefore 
provided instead of two. The old girders were used as the 
outer members. The two inner lines of girders are new. 
and these were conveyed to their position bv a traverser 
running on rails laid on the top of the outside-the old 
girders, and were subsequently lowered into position by 
lydrauhc gear mounted on the 'traverser. 

ie thirteen central spans are entirely new. and 

iese and all other work the metal was so arranged 

\ XI W ° Uld *' 0t exce *d 4 tons per square inch. 

ol4to!! nme T SpanS "*' '^^T lattice construction weighed 

* eai ''■ "'«! cost £47 per lineal foot. They were 



















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LIFTING THE NEW BIRDERS INTO POSITION. 



85 



built complete on pontoons, which fitted compactly into 
docks in a wharf on the shore of the Firth. 

So perfect was the constructional plant that seventy- 
two days sufficed for the erection and riveting of each 
span, four hours for the floating of it into position, and 
twenty-one days for the hoisting of it on to its bed- 
plates. 




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Raising Centre Span Girders on to New Piers! by Hydraulic Jacks. 

The span was so erected on the pontoon that when it 
was moored between the piers, and the tide fell, the bottom 
of the girder work was level with and rested upon the 
top of the brickwork surrounding the girders between the 
two cylinders of each pier, 1 ft, 6 in. above high-water 
level. An open space had been left from top to bottom 
in the shell-plating of the wrought-iron piers for the 
insertion of the ends of the girders. Thus the piers and 
the permanent bracing within them were utilised, along with 
a temporary "lifting" column of angles in the interior, for 






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MATERIAL USED: COST OK BRIIXIE. 



the raising of the span step by step. On the bottom of 
the girder-work there were temporarily fitted hydraulic 
rams, one at each corner. The head of the ram cylinder 
hutted against a girder held transversely in the temporary 
column within the pier by pins inserted through the 
bracing and angles. The rains, working against this 
girder, raised the complete span a few inches, when a 
second temporary girder was pinned into position, again 
on the "lifting" column, to support the span while the 
ram receded into its cvlinder. The temporary girder 
on which the ram found its abutment was next raised a 
distance equal to the stroke of the ram. Thus, step by step, 
the span was raised to its ultimate position through total 
heights varying from 47 ft. 6 in. to 68 ft. 6 in. The 
plates of the piers, temporarily omitted for the insertion 
of the ends of the main girders, were then completed, and 
the span secured on its bed-plates. 

The bridge was designed to resist a wind pressure of 
56 lbs. per square foot. A parapet. 5 ft. high, is built 
where the trains travel on the top of the girders, in order 
to prevent the wind from exerting an upward force against 

the bottom of the carriages. At intervals of 500 ft. in 
the length of the bridge, provision is made by rocker- 

bearmgs for the expansion and contraction' of the 
girders. 

The 23,783 tons of iron used is of a strength equal 
^ a hreakmg tensile strain of 22 tons per square inch. 

-iu.i in!h Th 1S ° f Sted " fl °° rS ' etC " ° f 27 *"» P* 

aid 26 4 I L 1 Jhei ' e w «e 37.024 cubic vards of concrete, 

tions,^ t^ 

lineal foot TV i W ** £670 ><>00, about £64 per 

*a*y girders ftJU 7 *?* h in l mrt (llle to fche use ° f 

.> biiaeis from the old bridge 



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The Tower Bridge. 

FT1HE Tower Bridge is probably the finest example of 
bascule structure in the world. Designed by Sir 
John Wolfe Barry, Bart, and Sir Horace Jones, and built 
in 1886-1894, it gives a roadway of a minimum width of 
49 ft. across the Thames east of London Bridge. The 
bascules when raised leave a central opening 200 ft. wide 
for river traffic. 

The two open leaves weighing 1200 tons each, are 
raised and lowered by hydraulic power. Experience has 
shown that the time taken to open and close the bascules 
averages five minutes twenty seconds. They are raised 
on an average twelve times each tide. Even when the 
bascules are closed the clear height above high-water level 
is 29 ft. (i in. — sufficient to allow moderate-sized craft to 
pass under. 

There are three main spans across the river, two of 
270 ft. on the suspension principle, with the centre bascule 
opening of 200 ft. clear. The two river piers, each 70 ft. 
wide, make up the total length from shore to shore of 880 ft. 
There are long approach viaducts of granite arching. 

The foundations for the river piers were constructed 
by Sir John Jackson, Ltd., and rest on the clay bed of 
the river ; the load was limited to 4 tons per square 
foot. 1 There were sunk to a deptli of 19 ft. below the 

1 S«-e "Thames Bridges, from the Tower to the Source," by James Dredge, page 1 ; 
and "The Tower Bridge: Its History and Construction from the Date of the Earliest 
l'rojuct tu the Present Time,' by J. E. Tuit, M. Inst. C.E. 







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FOUNDATIONS Wl' TOWERS 




river bed eight caissons for ea«b pier, four on each face 
The caissons were each about 28 ft. square, and were founded 
34ft apart. At the ends there were sunk triangular caissons 
to form the foundations for the cutwaters. The interior 
of these caissons, and the space between them, was tilled 
with cement concrete. Upon these caissons the piers were 
built of brickwork with granite facing. Large voids or 
chambers were left in the piers for the hydraulic 
machinery, and for the short counterbalancing arm of 
the bascules. The total cost of the piers was £111,122, 
equal to £2.37 per cubic yard. 

The whole of the steel and iron superstructure was 

built by Sir William Arrol and Company. Each tower 
on the piers consists of four octagonal steel columns 
120 ft. in height, and each 5 ft. o' in. in diameter. From 
a height of 60 ft. above road level to the top the columns 
are connected together at intervals lev girders with heavy 
diagonal bracing. The towers on the abutments are gener- 
ally similar to those on the river piers, but are only 
44 ft. in height. 

The side spans are on the suspension principle. The 
roadway and footpath decking is carried on longitudinal 
stringers, borne on transverse girders (;i ft, long and 33 in. 
deep, which are hung at intervals of 18 ft. bv suspension 
tit-rods from two braced and curved supports, conventionally 
J alled "chains," but really heavy curved girders. The 
owest part of the chain is not, as is usual, in the centre 
ot the span, but is nearer the abutment to suit the 

fence in the height of the pier and abutment towers. 
, abutment the chains are anchored to massive 

Z^ b r U ««^ while the ends of the chains of 
^suspension spaM at the fer fc connected 

i} ) ties some 230 ft i , 

*wit Long, stretching between the piers at 






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the lewl of the upper footbridges. In tliis wa\ the loads 
on the two suspension spans are balanced 

In the bascule span there are two Leaves, each carried 
on a trunnion shaft placed in a recess in the corres- 
ponding pier. Each leaf is built up of four longitudinal 
main girders, 13 ft. 6 in. apart, with bracing and in- 
termediate girders to support the decking. The main 
girders extend to the rear of the trunnions, where there 
are formed chambers which carry about 350 tons of counter- 
weight for balancing each leaf on its turning shaft. 

The hydraulic machinery for opening and closing the 
bascules is located in a chamber in the pier. This machinery 
operates, through -earing, a quadrant on the girders of the 
bascule, which is thus tilted from the horizontal to the 
vertical position for opening— (a- backwards to the hori- 
zontal for closing— the passage for ships. The engraving 
on the opposite page shows the bascules open. 

In the bascule span, high above the main level of 
the roadway, there are two foot-bridges. To these access 
is provided by means of stairways and hydraulic lifts 
^thm the towers. These foot-bridges have a span of 
about 230 ft.; they are 141 ft. above high-water level. 
"J are quite independent of each other, and each has a 

tn,,u Y L2 ft. wide. The bascule is. however, so quickly 
T' 1 "; '"« closed for the passage of river traffic, that 
;;;;;- <* pedestrians, as well as to vehicular traffic, is 
^ghgblea nd the high- level bridges are never used. 

235,000 cnhie r, ;;:! ni : ti,,n ? f the *««■ *« — -> 

of cement 70000 K- g * a * d ° ther stone > 20 ' 000 toBS 
and 14^ 

bridge was ^s^i^o 11 ' 011 ^ BteeL The total cost of the 



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lu iUl - John Gass, tlie 



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WORKING THE BASCULE? 



the bridge, for the following particulars relating to the 
working of the bascule span : 



Time taken to dear the traffic off the bascules 

Time taken to withdraw the locking bolts 

Time taken to lift the bascules through an angle of 82 dog. 

Time taken to allow vessel or vessels to pass 

Time taken to lowei the basc'ules 

Tim.- taken to shoot the locking bolts and resume traffic 



>nds. 

25 
90 

■ 
90 
25 



The average delay to the vehicular traffic per lift 
was 5.5 minutes in 1899, 5.25 in 1900. 5.22 in L901, 5.33 

in 1902, 5.07 in 1903, 5.00 in 1904, and 5.00 in 1905, 
and it lias since then continued at this period. The 
average number of openings of the bascules per day 
of twenty-tour hours was 22.41 in 1900; 23.71 in 1901; 
25.23 in 1902; 25.10 in 1903; 24.27 in 1904; and 23.78 
in 1905. During the first year after the opening of the 
bridge the average number of openings per day was 17. 
Ihe number of openings on one day has reached a 
maximum of 55; this has occurred on two occasions. 

Under ordinary conditions an average of 87 horse- 
power is exerted by the hydraulic engines in opening and 
closing each bascule. 






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Road Bridges over the Nile at Cairo. 





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JN the summer of 1903 the Egyptian Government issued 
specifications inviting tenders and designs for three 
road bridges to be constructed over the Nile at Cairo. 1 

For each bridge thirty-eight designs and tenders were 
received from thirteen firms, six of whom were French, one 
each German, Belgian, Italian and Swiss, and three British, 
one of the latter submitting an American design. 

A Commission was appointed to examine the designs 
and calculations and report to the Government. After 
a careful and prolonged examination of the various 
proposals, the designs and tender of the joint firms of 
Sir William Arrol and Company, Limited, of Glasgow, 
and Messrs. Head, Wrightson and Company, Limited, of 
Middlesbrough, were accepted for constructing the three 
bridges. The successful designs were prepared by the 
Civil Engineering Staff of Sir William Arrol and Company, 
Limited. 

The principal bridge spans the Nile from Ghizeh, near 
the road to the Pyramids, to the Island of Rodah, and 
the two smaller bridges connect Rodah Island with the 
main road leading to Old Cairo. 

A double line of tramway of one metre gauge passes 
over all the three bridges, and connects up the Cairo lines 
with the one to the Pyramids. 

The position of the main bridge required careful 

1 See Engineering, vol. Ixxvii., page 682 : vol. Ixxxi., page 42; vol. lxxxii., page 483; 
v-.l. Ixxxiv., page 3i2 ; vol. lxxxv., page 40. 



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ESTHETIC AND ARCHITECTURAL KKAITI 




attention to be given to the aesthetic effect of the design, 
a point too often forgotten in designing such structure. 
It was considered that many people would regard the 
larger bridge not merely as a means of crossing the river, 
but as offering special facilities to enjoy the scenery and 
cooler atmosphere in the vicinity of the Nile, and conse- 
quently it was most desirable that no portion of the 
structure should in any way interrupt a clear view of 
the river and city of Cairo. 

« 

The masonrv abutments at the entrance to the main 
bridge have substantial masonry pilasters of an Egyptian 
character, designed to be in accordance with the dignity 
of the undertaking. Provision is made that suitable 
statuary may be placed on the pilasters if considered 
desirable by the Egyptian Government, The principle 
adopted throughout the design was to adhere to a form 
which was structurally correct, while adopting an archi- 
tectural treatment which would emphasise the construction 
and give suitable expression to the structure. The general 
effect is pleasing, and when viewed from the river banks, 
the bridge has a graceful appearance. 

The main bridge is 1755 ft, or about one-third of 
a mile, m length between abutments, divided into ten 
spans of 140 ft., two end spans of 70 ft., and a double- 
swing span 220 ft. in length with two clear openings of 
><> £ Ihe bridge is M ft. in ^^ between parap ete, 

unided into two footpaths 8 ft. wide, and a roadway of 
50 it. m width. 

ie PW» of the bridge are formed of steel cylinders, 
lo-ul \ \, T er at the base ' fil1 ^ 1 with concrete. The 

making a l t TT ° f !** ° ylinder is about 140 ° t0 " S ' 
Over 7000 V I Dearly 40 ' 000 toils °« the foundation* 

tons of steel and iron were used in the work. 



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One of the Two Bridges between Rodah Island and Cairo. 




The Main Bridge across the Nile with its Test Load. 



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The electrically-operated swing span, illustrated on the 
Plate facing page 94, is 220 ft. in length, weighs nearly 
1000 tons, and is opened or closed in three minutes, in- 
cluding all operations. Provision is made against an 
interruption of the electric current, and two men can 
open the bridge by manual power. 

To found the cylinder piers it was necessary to remove 
about 16,000 cubic yards of grey sand, and this was done 
under air pressure. The foundation work was completed one 
month ahead of time, notwithstanding some early delays 
in commencing operations. The whole of the sinking was 
done by native labour under European supervision. 

Considerable difficulty was experienced in getting 
labour for the work of building and riveting the steel 
superstructure. The general prosperity of the country 
caused suitable native labour to be scarce, and such as 
could be obtained had to be specially trained under 
European foremen to work the pneumatic and hydraulic 
riveting machines. Over half-a-million rivets had to be 
put in at the site, and great credit is due to the staff 
for the careful supervision exercised, as the total per- 
centage of defective rivets which had to be replaced was 
almost the same as obtains at home with skilled white 
labour. With regard to this point, the late Sir Benjamin 
Biker reported to the Egyptian Government that the 
work done by the native riveters was of a satisfactory 
quality. 

The erection of the whole of the steel superstructure 
was completed fully two months ahead of the forecasted 
time of the programme made out at the beginning of the 

work. 

The bridges were officially tested by the Government 
with most satisfactory results. The various operations in 



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• . B nan were carried out weU 
♦• „ wit* the opening spa f this bri dge » 

- ,um ' Ct r ,Hied time. The const «***? SirW mia m 
*'S t the ioiut contra,^ Mej- n 

*d Company, I**** f , the report of the ate 

fonly necessary to ;,«• f Mc t he states :« I ^e to-day 
Sir Beujamiu Baker xu which bridge) and a* 

? bruary 1st, UKKT, in8 ^ 8 ^ at erial and workmanship 
IX to certify that as regards "a ^ the 

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most modern appliances. 
















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Bridge over the River Wear at 

Sunderland. 



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rpHE new double-decked railway and road bridge over 
the River Wear at Sunderland/ with railway and 

roadway approaches, was constructed from the designs 
of Mr. Chas. A. Harrison, M. Inst. C.E. The bridge and 
approaches have a total length of about If miles, and they 
formed one of the largest bridge contracts let in this country 
since the Forth and Tay Bridges, which were built by the 
same firm. The contract included the whole of the works 
for a double-line railway throughout, and for the street 
approaches and the roadways over the bridge. The main 
bridge has two decks, the upper deck carrying a double- 
line railway track for the North-Eastern Railway Company, 
while a roadway and footways are carried on the lower 
deck and provide communication across the river between 
Sunderland on the south side of the river and Southwick. 
About 8500 tons of permanent steelwork was required 
in the construction of the bridge, as well as 500,000 cubic 
feet of granite, 60,000 tons of red sandstone from the Locliar- 
briggs Quarries, near Dumfries, one third of a million 
bricks, and about 300,000 cubic yards of spoil in the 
banks and cuttings. 

The general design of the bridge is shown on the illus- 
tration opposite. The total length of the bridge proper 
is 15G0 ft. The northern approach between the railway 

1 See Engineering, vol. Ixauriv., page 4-'i : \«\. lxx.wi., |. a .... .-,33. 



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AN EXCEPTIONALLY LARGE CAISSON. 



embankment and the north abutment is formed of seven 
stone arches carrying the roadway and footways, and 
supporting the steel trestles for the railway tracks. The 
railway and roadway approach each other at an angle, 
and intersect on the north abutment. Between the north 
and south abutments are two land spans of 200 ft. on the 
north side of the river, a river span of IYM) ft. clear, and 
a land span of 200 ft. on the south side of the river. From 
the south abutment to the embankment the roadway is 
carried upon stone arches surmounted by steel trestles 
for the railway tracks as on the northern approach. 

The foundation for the main river pier was sunk, 
under air pressure, to 75 ft. below high water by means 

of an immense rectangular caisson, 63 ft. long by 35 ft. 
wide. The caisson was tilled with concrete to facilitate 
sinking. A large chamber, open at the bottom, was left 
in the caisson so that the men could work inside and 
excavate the soil, which was removed through shafts in 
the roof of the chamber and passed through air locks 
to the open. When the caisson reached the final depth, 
the chamber was completely filled with concrete, so as to 
provide a large surface to distribute the great weight to 
be home on the foundation. The usual temporary caisson 
or cofferdam above the permanent shoe was dispensed with 
■n sinking these piers. The masonrv of the pier was built 
up above high water as the sinking proceeded. After the 
sinking was completed, the granite piers were continued 
up to the girder seats about 85 ft. above high-water level. 
ine total weight of each completed pier is about 16.000 tons, 
and it carries on the top of it a tota] load of 4:m ta 

nie land spans consist of two parallel main girders, 

suit- I , e 7 aUd 3 ° ft dee P' P lace d 32 ft. apart, with a 
k fl ° 01 ' sus P eu ^ from the horizontal bottom 






& 



THE RIVER SPAN. 



99 



members. The railway floor is placed between the main 
girders, so as to allow a clear headroom of 18 ft. above 
the roadway. Each land span weighs about 1000 tons. 
They were built in their place on staging formed of three 
timber piers, with suitable girders on their tops to sup- 
port the weight of the span. 

The river span illustrated on the following pages is 
formed of two main girders, and is 353 ft. long and 
42 ft. deep in the centre of the span. The road and 
railway floors are similar to those for the land spans. 
The weight of steelwork in this span is 2600 tons. 

The erection of the span over the river required con- 
siderable engineering ingenuity and judgment on account 
of the exceptional difficulties to be overcome. On each 
side of the river are shipbuilding yards, from which the 
ships are launched into the water immediately under the 
bridge. In the Act of Parliament permitting the con- 
struction of the bridge it was expressly stipulated that 
the river was to be kept clear at all times for navigation. 
It was left free to the contractors to erect the bridge in 
any manner which would not encroach on the navigable 
waterway. To put staging in the river upon which to build 
this span was clearly out of consideration. 

After consideration of various schemes, Sir William 
Arrol and Co. decided to convert the river span temporarily 
into cantilevers and build it out from each pier, piece by 
piece. In building the central girder between the pro- 
jecting cantilevers of the Forth Bridge a similar method 
was adopted, but although the central girder of the Forth 
Bridge and the river span of the Wear Bridge are of exactly 
the same length, the weight of the Forth Bridge girder 
was only 850 tons, or one-third of that for the River Wear. 

The valuable experience gained by Sir William Arrol and 

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1LI ,IN<; THE KIVKK SPAN. 



Company, Limited, at the Forth Bridge was of especial 
value when dealing with the greater problems presented 

in the erection of the river span of the Wear Bridge. 

The first portion of the span was built upon the pier, 
and the top of the girders tied back to the end posts of 
the land span which rested on the same pier. These ties 
were of sufficient strength to enable about 75 ft. of the river 
span to be built out from the pier. \\ bile this portion was 
being built, a steel tower 70 ft. high was erected upon the 
portion of the river span immediately above each pier, and 
the top was tied back to the farther end of the adjoining 

land span. From the top of each tower steel ties were 
brought down and connected to the girder at points 
about 70 ft. from the pier, which allowed the river 
span to he built a further 48 ft. from each pier, where 
other ties from the top of each tower were connected to the 
bottom members of the main girders. When these ties 
were comieeted the river span was built out to the centre 
of the river, 170 ft. from the piers. At this point careful 
measurements were made and sent to Glasgow, where the 
closing lengths were made and forwarded to the site. 

The placing of the closing lengths in position, and 
the riveting of them up, was an operation requiring great 
care and judgment. Variations of temperature caused the 
projecting ends of the girders to rise and fall from £ in. 
to 4 in., and to approach and recede from each other 
from 1 in. to ^ in., while the sun caused the ends to move 
westwards as much as i> i„. in the morn ing and again 
eastwards in the afternoon. The closing measurements 
were made on a dull day, when the temperature was 
""■torn, and only under the same conditions could the 
3J len - ths U ^ir Places. To be independent of the 
' * l0nS 0f tei "perature, special provisions were made. 






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THE MAGNITUDE OF THE TASK. 



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At the ends of the land spans an hydraulic arrangement 
was fitted to push or pull the girders horizontally, and 
under the ends of these spans hydraulic jacks were placed 
to raise them, and thereby vary the levels at the centre 
of the river span. These special provisions, however, were 
not required, as the ends came together accurately under 
normal temperature conditions. 

When the riveting of the closing lengths was com- 
pleted, the temporary ties were relieved of stress, to permit 
of their removal, by raising the ends of the land spans a 
sufficient height to allow all elongation in the ties to be 
given up, and the main girders of the river span to settle 
down under the reversal of stress in the booms. 

The magnitude of the task is evident from the fact 
that about 800 tons of steelwork was employed in the 
temporary work for erecting this span. It was realised 
ly Sir William Arrol and Company, Limited, that enor- 
mous risks were being undertaken, and the greatest care 
was given to the temporary work to get an erection 
scheme of safe, substantial, and economical character. The 
plant and temporary steelwork for the erection was accu- 
rately made. All the joints in the temporary ties and 
towers were made with turned steel bolts of a hard 
driving fit, accurately turned to gauges, and fitted by 
mechanics. About 20,000 bolts were used, and several 
tests of their shearing strength were made under circum- 
stances similar to their working conditions. Some idea of 
the enormous forces dealt with may be had from the 
knowledge that the stresses in the back ties of each half 
.pan amounted to about 1200 tons, and in the front ties 
to 1400 tons. The maximum weight suspended from the 
temporary ties before the closing lengths were fixed was 
2400 tons. To ensure that the temporary ties took the 



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HYDRAULIC STRESSING GEAB FOR PEMPORART TIES. 



portion of the load for which they were desij ed, ,„ 
hydraulic 'stressing gear of unique design, capable of 



exerting a force of 800 tons, was employed in puttin 



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initial stress in each tie. 
This -ear was tested to 
1200 tons before leaving 
the contractor's works. The 
hydraulic screw jacks are 
illustrated on this page. The 

ram had a screw thread 
upon it. and engaged with 

a nut where it projected 
through the cylinder. As 
the rain was forced out of 

the cylinder by the hydraulic 

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pressure, the nut was kept 
continually screwed back to 
maintain constant contact 
with the top of the cylinder. 
In the event of failure of 
the hydraulic pressure, it 
was impossible for the rani 

to run hack, and it could be 
held ' 

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Hydraulic Stressing tiear on 
Temporary Ties. 



m any desired position for any length of time to 
' any operations to be carried out. 









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The Scherzer Rolling=Lift Bridge 

Over the Swale. 

rPHE engravings on pages 105 and 107 illustrate the 
-*- Scherzer Rolling-Lift Bridge, which carries the main 
line of the South-Eastern and Chatham Railway, and 
the public highway, across the Swale, in the County of 
Kent, 1 The span is 62 ft,, and the total width of the 
bridge between the centres of the girders is 33 ft. The 
total weight of metal in the bridge is 962 tons. 

The bridge which it replaces was a double bascule, 
operated by hand-power, and built about 1862. The new 
structure was designed by the late Sir Benjamin Baker, 
K.C.B., who decided to adopt the Scherzer type, in which 
the rolling weight of the bascule is balanced and heavy 
gearing dispensed with, whereby friction is minimised. 
Thus on the official trials the whole span, weighing 
.~>20 tons, was opened in fifty seconds, with the motor 
developing only 9 brake horse-power. 

Great interest is associated with the foundations, as 
the old piers had to be underpinned The cutwater ends 
of the old piers were first taken away, to enable new steel 
caissons to be sunk for four new piers. These are founded 
at a greater depth than the cast-iron piles, which constituted 
a feature of the old piers. The old bridge foundation was 

1 Engineering, vol lxxix., page 7(3 l>. 



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104 



THE LIFT SPAN. 




rirt underpinned with timbers, and steel beams were passed 
through the heart of the old brick piers, which were 
hollow The upper walls of the old piers were then partly 
cut away for a sufficient depth, to allow heavily-braced 
cross-girders to be put in position between each pair of the 
new piers. These girders carry the new superstructure. 

The Scherzer system also offered the special advantage 
that erection could proceed without interference with the 
traffic either of the railway or the highway. The rolling 
span was built and riveted together upon a platform over 
the old structure, and was subsequently lowered into 
position within the short period when traffic had cased 
between Saturday night and Monday morning. The 
staffing was erected over the old bascule span and the 
approach span immediately behind it. It was supported 
on steel girders and posts, and on it were carried also 
the necessary cranes, etc., for the construction of the new 
Scherzer span. The railway and highway beneath were 
thus entirely free for the passage of traffic during the 
progress of construction of the new span. 

For the tilting mechanism of the rolling Scherzer 
span, there are four strong braced girders outside of, 
and parallel with, the old girders of the approach span, 
which was retained. The new longitudinals carry track 
girders with a planed flange and projecting teeth, in 
which engage the geared segmental girder of the Scherzer 
lift span, well shown in the engraving on the opposite 
page. The circumferential surface and teeth were milled 

The lifting span, 65 ft. long between centres of bearings, 
had been built and fitted temporarily at the Dalmamock 
Works of the Company, and the parts duly marked were 
forwarded for final erection and riveting on" the site. This 
span is composed of two outer braced girders, and a centre 



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WORKING IIS i: LIFT SPAN 



plate well girder, which serves to divide the roadway from 
the railway. The floor surface is of steel plating, covered 
with asphalte on the railway side, and planked for the 
roadway. This is illustrated in the view on the opposite 
page, showing the rolling-lift span open for the passage of 
river traffic. The single line of railway crossing the bridge 
is attached to longitudinal timbers laid in troughs. 

The segmental girders curving backwards from the 
end of the posts at the rear of the Scherzer span carry on 
their upper terminations counterweight boxes, containing 
a sufficient weight of metal to balance the lifting span; 
and this kentledge is so disposed as t<> be in exact 
counterpoise with the span in any position. 

Carried on the approach trusses over the roadway 
and railway are the platform and houses for the accom- 
modation of the operating gear. The dynamo, driven by 
an nil engine of 9A brake horse-power, supplies storage 
batteries from which the motors take their current. 

There is also an emergency hand-gear for lifting and 

lowering the span. 

Alongside the engine-house there is a signal cabin, 
from which are controlled the operating machinery, the 
signals, the locking gear, the gates on the railway and 
roadway, etc 

« 

Notwithstanding the difficult work in connection with 
the foundations, the total cost of the bridge was only 

£38,500. 



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Viaducts Over the Rivers Barrow and 



in Ireland. 



rpHE next typical structures which we select for de- 
scription are viaducts over the Rivers Barrow and 
Suir, near Waterford, Ireland. Both are interesting; 
the first-named is the longest viaduct in Ireland. The 
two bridees constitute important links in the chain of 
communication inaugurated in L906 as a now route 
between London and the South and West of Ireland. 

The passenger travels over the Great Western Rail- 
way from the Metropolis to the new harbour of Fishguard, 
in Wales, a distance of 262 miles. Thence there is a 
day and night service across St. George's Channel to a 
new harbour at Rosslare, in Ireland. 54 nautical miles 
distant, by three new turbine-driven steamers, with a speed 
of 22{ knots. 1 From Rosslare a new line, 38 miles in 
length, has been constructed to Waterford, joining there 
with the system of the Great Southern and Western 
Railway of Ireland, communicating with Killarney and 
other tourist districts. The new route shortens by 100 
miles the journey between London and some of the most 
beautiful districts in Ireland. 

The specially notable features of the works in Ireland 
were the long viaducts across the rivers Barrow and Suir, 
the former on the new main route, and the latter linking 

' Sce Engineering, vol. Ixxx, page 17s ; v .,l. Ixxxii. page 106. 







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GENERAL DIMENSIONS, 



109 



the new line with the existing Waterford, Dungarvan, and 
Cork line of the Great Southern and Western system. 

4 

For the new works Sir Benjamin Baker, K.C.B., was chief 
engineer, in collaboration with Mr. James Otway, one 
of the engineers of the Great Southern and Western 
Railway of Ireland. 

The Barrow is a broad river, with a relatively narrow 
navigable channel of great depth — 39 ft. 9 in. at low 
water — on the Kilkenny side. The Suir is somewhat 
similar, and both rivers join where they enter the broad 
estuary which constitutes Waterford Harbour. The River 
Barrow is crossed by a single line of railway, 5-ft. 3-in. 
gauge, 100 yards above its continence with the Suir, and 
about 6 miles from the town of Waterford ; while the 
Suir is spanned 1 mile above Waterford. 

The superstructures of both bridges are alike. The 
Barrow Bridge is 2131 ft. long between the faces of 
the abutments, and consists of thirteen fixed spans, with a 
swing-span over the river, giving a passage 80 ft. clear 
for the traffic on each side of the centre dolphin. The 
Suir Bridge is 1205 ft, in length, also between abutments, 
and includes six spans of 148 ft., one of 133 ft., one of 
102 ft. 9 in., and an opening span — in this case of the 
Scherzer rolling-lift type — of 50 ft. in the clear. 

Interesting timber work was involved at the Barrow 
Viaduct, not only in the forming of the temporary staging 
for the sinking of the piers, but also in the construction 
of the swing-span dolphin. This latter extends for a 
distance of 150 ft. in line with the river, and is 39 ft. 
in width at the centre, tapering to 25 ft, at the ends. 1 

In the construction of the bridge interest was largely 
centred in the piers, as several of these had to be 

Engineering, vol. lx.wi., pages 673, 716, 780, and 841. 



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CONSTRUCTION OF PIERS Wl> 3IRDBRS, 




sunk to great depths, the maximum being 117 ft. below 
high-water level. The air pressure reached 43.5 lbs. per 
square inch. On pages 16 to 18 we have described the 
procedure and illustrated the piers : while on page 
details are given of the compressed air-locks. 

The two cylinders forming each of the piers are braced 
at the top by cross capsill girders, which form the seating 

for the main longitudinal girders. These are 20 ft. deep 
over angles, and are spaced at L6 ft. (> in. centres. Each 
girder is constructed in eight bays, designed so that no 
rain water may lodge in any part. 

The girders were built in sections at the Glasgow works, 
and despatched to the site, where they wore erected in 
position on wooden trestles placed on the temporary 
staging, the complete span being thus put together ready 
for lowering on to the bearings. The cross girders carrying 
the permanent way are at from IS ft. to 11) ft, 3 in. 
centres. The bottom lateral bracing consists of angles 
riveted to gusset plates at the base of the vertical pots 
of the main girders. The lattice bracing on top is clearly 
illustrated in the view on the opposite page. The 
portal bracing there shown was erected at the ends of 
each span, and forms the terminal member of the system 
of top lateral bracing; it ties together, and forms the 
strap between, the upper part of the raking-posts. 

^e turn now to the pivot piers and the swing span, 
which, with its moving parts and live ring, weighs 303 
tons. The pivot pier for the swing span consists of four 
cylinders, braced, on both the transverse and longitudinaJ 
toes by ties extending 20 ft. below water level. 

Hie girder framework, for carrying the roller path. 

* Pivot, and the live rollers of " the swing span was 

111 upon the main capsill girders resting on the top 



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of the tour piers. These form a rectangle supporting a 
framework riveted and set perfectly level in position, before 
the concrete filling of the cylinders was put in, prior to 




The Viaduct over the River Barrow. 



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the bed-stones of the main capsill girders beinj 
up. The support for the circular track for the live roller- 
ring was thus made perfectly true to level. The concreting 
was then completed, and its surface coated with asphalte. 
At the centre of this framework there is a largq 



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foundation plate, octagonal in plan, on which the pivot is 
bedded and held in position by bolts. The holes for these 
bolts were bored on the site after the pivot had been set 
in position, as great care had to be taken to see that the 
pivot was dead true in the centre. 

The live roller-ring is carried on this girder frame- 
work. The engraving on pa^e 7 i^ives a clear idea of 
this ring, and of the centre pivot round which it rotates. 
The pivot is of east steel, and affords a bearing around 
the complete circumference for supporting a ring-plate, to 
which are connected the radial rods extending to the 
rollers. On each rod there is an arrangement for adjusting 
its length. The rollers are of wrought steel. 

On the tops of the rollers a circular girder was built. 
This is known as the "drum" girder, and to the under- 
side of it there is bolted the cast-steel tread rest in- on 
the live rollers. The drum girder, which is '1\\ ft. 4 in. 

in diameter, thus constitutes a circular support trans- 
mitting the weight of the swing span to the top of the 
live rollers. A series of girders connect this circular 
support with a central framework carrying the steel 
pivot ring. This ring conveys no weight to the pivot, 
but transfers to it all lateral pressure. 

The swing span is 214 ft. 6 in. Ion-'. In the top 
boom of the centre panel of the girders there are transverse 
members supporting the operating machinery room, which 
is thus over the railway track. On a still higher level is 
tHe look-out cabin, in which there are located the levers. 
not only for the signalling gear, but for operating the 
™Jge. relegraphic and telephonic connection is made 
W ™ la *d on -each side of the bridge. 

eleet "' "!' 1 ' t ' Vr PmV "'' ''*'*■ grating 'the swing span is 
' mth emer gency hand-gear. The power equipment, 






















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MOTIVE POWEB I "If SWING SPAN. 



located in a power-house on the dolphin, consists of two 
J)' brake horse-power oil engines driving dynamos generating 

electric power at L50 volts, which is stored in (>1 cells of 
the Tudor make. The time taken to fully charge these 
cells, when both engines are running, is six hours; the 
fuel consumption is seven to eight gallons of oil. 

The contract condition that the swing span should 
be opened and closed in two minutes was fulfilled without 
difficulty. The weight to be turned, including the live ring 
is 303 tons. Two turning motors in the machine-room, 
each of 20 brake horse-power, singly or together rotate 
the main horizontal shaft, through friction clutches adjusted 
to a maximum transmission of 20 brake horse-power each. 
From this main shaft the power is transmitted by bevel 
wheels to two vertical shafts at opposite corners of the 

structure. These connect by spur gearing at their lower 
ends with the driving shafts attached to the drum girder. 
The last-named shafts carry the driving pinions, which 
engage with the rack fixed to the to]) of the pivot. The 
turning of the rack swings the opening span. 

There are also provided electrically-driven lifting jacks 
at each end of the swing span, to lift it from its end 
hearings before it is swung. There are locks to secure 
the bridge in its seating when closed. 




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The Caledonian Bridge Over the River 

Clyde at Glasgow. 

rpHIS bridge is one of the broadest and most substantial 

- 1 - structures yet built, carrying nine lines of rails across 
the River Clvde into the new Central Station at Glasgow 
of the Caledonian Railway Company. 

The new structure was built in 1904-5 alongside an 
earlier bridge, also constructed by the firm in 1875-78 (see 
page 4). It is part of extensive reconstruction work at 
the station, necessitated by the great increase in traffic 
into this Glasgow terminus. 

The new bridge was designed by Mr. Donald A. 
Matheson, M. Inst. C.E , the chief engineer of the Caledonian 
Railway Company, and is remarkable no less for its great 
strength than for its economy in construction, the cost 
working out at about £3 per square foot of decking. The 
river is about 410 ft. wide ; the bridge, with the adjacent 
street spans, has a length of 752 ft., and an average 
width of 120 ft. The weight of steel work employed in 
its construction totalled 11,000 tons. The principal spans 

are 160 ft., 200 ft., and 178 ft. 

For forming the foundations, steel caissons were sunk 
under compressed air: six for the shore piers, and two for 
each of the river piers. These latter were sunk to a depth 
of over 80 it. below high-water level, into hard sand and 
gravel. The piers which are built on these foundations 



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are of red brickwork, Paced with blue brick up to near the 
low-water level, and with light granite thence to the cope. 
The superstructure of the river spans is of steel lattice- 
airders; there are ten girders in the width of the bridge, 
and the spacing between them increases as the bridge tans 
out towards the station on the north side of the river. 
The spans over the streets at each end of the l.rid-c are 
of web girders. The flooring, of Eobson's trough type 




View along the Bridge. 

on the river spans and of buckle plates on the street spans, 
is on the top of the main girders: tins permitted points 
and crossings to be introduced wherever desirable. 

An ornamental lattice parapet, with cast-iron cornice, 
cope, and rosettes, is carried out from the outer main 
girders on ornamental steel brackets, ami gives a graceful 
appearance to the bridge, as shown on the engraving «'» 
theopposite page. The brackets carry a footpath fully 5 ft 
wide along the whole length of the bridge, for the use of 
workmen and officials. 




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LIFTING A BRIDGE WITH HOO Ton SPANS 




Sir William Virol and Company, Limited, were also 
entrusted with the raisin- of the old bridge by nearly 3 ft., 

to coincide with the level of the new bridge and of the 
greatly enlarged Central Station. In the old bridge there 
are five spans, varying from 200 ft. to 163 ft. j with 
two shore spans 70 ft. and 100 ft. respectively. There 
are two main girders in each span, at 50-ft. centres. The 
floor is carried by cross girders resting on the bottom 
booms of the main girders. The main girders in the 
river spans are braced overhead. 

As soon as traffic could be transferred to the new 
bridge the work of raising the old structure was com- 
menced. This was early in October, 1905, and the 
work was completed and the bridge reopened in April. 
1906. The first span raised was the centre one. of 200 ft. 
in length and 800 tons in weight. Large plate brackets 
were secured with turned bolts at each end of the two 
main girders, and two hydraulic jacks were placed under 
each bracket. The eight jacks were connected to the 
same pump, which worked at a pressure of L800 lbs. per 
square inch. Hardwood packings were inserted from 
time to time between the masonry of the pier and the 
bearing-plates, so that at no time was the space between 
the bearing-plate and the packing allowed to be greater 
than one quarter of au inch. The lifting was continued 
•^out 3 m. higher than the ultimate level, in order to 
«'iow a stool to be put in place underneath the bearing 
P »a Ihese stools were built of steel plates and angles, 
Lkhed m P and . bottom and brought to the site 

them Ti l yl VUt 1U pliK ' e ' the s P an Nva * lowered upon 

"« lilting brackets were then taken off, and 
ourxea on to the mrdeix Af fk< * • i 

gmiers oi the next span to be raised. 













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The Redheugh Bridge over the 

River Tyne. 



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rpHIS bridge, 1 of which an engraving is giveD on page 
15. was designed by Messrs. Sandeman and Moncrieff, 
MM. Inst. C. E., of New castle-on-Tyne, and carries the road 
traffic between Newcastle and Gateshead across the River 
Tyne, at a point where the waterway is about 850 ft. 
wide. The problem was to build a bridge requiring deep 
foundations and long spans on the same site as the old 
structure — which was not in a safe Condition — without 
interfering with the traffic. 

As shown in the section of old and new structures 
on the next page, the old bridge was supported on cast- 
iron piers, and the superstructure was built up of braced 
girders having tubular booms, which were used originally 
as mains for the passage of gas and water across the 
river. Preparatory to the building of the new bridge, 
large timber trestles were constructed to protect the old 
piers, and to temporarily support the old girders during 
the process of constructing the new bridge. At the same 
time, extreme care had to be exercised to prevent settle- 
ment dining the sinking of the caissons for the new 
piers. 

While new approaches were being made of girder 
work carried on masonry piers, with a large abutment pier 

1 See Engineering, vol. lxxii., pages : > : »", 644. 



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I UK FOUNDATIONS AM' PIERS. 



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on each bank of the river, the difficult work of sinking the 

new foundations was proceeded with. For the four spans 

across the river three piers were 

made, each composed of four 

cylindrical caissons sunk to a 

depth of 6.5 ft. below high-water 

level, into a firm bed of shale. 

These caissons were filled with 

concrete, and strongly braced 

in pairs. Steel columns were 

built upon the caissons, with an 

inward batter towards the to]). 

where a strong platform of 

girders was constructed, uniting 

together the four columns in 

each pier. These "irders, of 

lattice work, measured 48 ft. 

over all, and carried the main 

longitudinal members of the 

bridge. These latter were built 

as cantilevers in both directions. 

until a junction was formed 

with the girder work from the 

neighbouring pier. The girders 

are of lattice construction, with 

N bracing and intermediate 

struts and posts. The two 

spans adjacent to the shore 

a,v *<** 168 ft., and the two 

nver spans 248 ft. each. The 

loi 




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! "" 1 fche Sorter 26 ft. 10 j,, ,,,,' 
tW0 1,,i,hl hagitudina] girders 



Section shoeing Old and New 
Redheugh Bridges. 

For each span there aic 

s, spaced 23 ft. centres apart. 



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THE GIRDERS AND ROADWAY 



As the girders have raking, instead oi vertical, end posts 
(see engraving on pages 15 and 121), it was necessary to 
temporarily continue the upper chords over the piers, and 
this was done by means of ties in which toggle gear was 
introduced. These temporary ties were kept in tension 
owing to the overhang of the girders when in course of 
construction as cantilevers. The toggle gear permitted 
adjustment to be made at any time, but particularly when 
the work of joining up the projecting cantilever arms in 
the middle of the span had to be undertaken. 

The longitudinal girders were built parallel to the 
old girders as shown in the section on page 120. but at a 
slightly higher level, while traffic was passing to and fro 
on the bridge. When completed, the new girders were 
lowered to the finished level by hydraulic jacks, and the 
cross girders for carrying the roadway were put in. partly 
in trenches across the old roadway and partly from below 
the deck of the old bridge. The new floor was then 
finished in sections: it is of buckle plating covered with 
concrete, on which wood paving is laid. 

A\hen the spans were thus completed, the old girders 
were removed piece by piece, and the new structure was 
moved laterally, again by hydraulic power, into its correct 
position <)n the cross girders on the piers. 

rhere is a footpath outside of the main girder on 
each side, and the gas and water mains are carried at 
the extreme ends of the cross girders. The weight of 
wec-i in the superstructure is o 75() t< ftnd the cost f 
the whole work was about £82,000. 




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The North Bridge, Edinburgh. 1 

TN 1895 the firm reconstructed the North Bridge, which 
-*- connects the old town of Edinburgh with Princes 
Street, a thoroughfare rightly regarded as the most pic- 
turesque in the United Kingdom. The bridge spans the 
valley at a point where this depression is occupied by 
the Waverley Station of the North British Railway ; 
the view on page 125 shows the station in course of re- 
construction, with the bridge beyond, and the historic- 
castle in the distance. 

The bridge, which was designed by Messrs. Blyth 
and Westland, of Edinburgh, differs from those which we 
have described, as its main feature is three segmental 
arches of 175 ft. span, springing from piers 18 ft, wide. 
The general effect is graceful, and worthy of the surrounding 
architectural and scenic features. Each span consists of 
six arched girders springing from abutments at each end, 
or from intermediate piers. The headway above rail 
level under the bridge is 2S ft. 3 in. at the springers at 
the north abutment, and 49 ft. 8 in. at the south abut- 
ment ; the roadway is from 78 ft. to 79 ft. above rail level. 

The piers, which are built of solid masonry, are 96 ft. 
6 in. by 18 ft, with octagonal ends. The abutments are 
s2 ft, by 33 ft., and are square on the springing face. 
The cast-iron springers are of massive construction, and 
receive heavy cast-iron rockers, upon which the arched 

i Engineering, vol. Ixviii., pages 123, 491. 



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124 



ARCH SPANS. 



ribs abut These castings are 18 ft. long and 4 ft. 7', in. 
in height, and each weighs 13 tons. They pass through 
the pier from side to side. The six arched web girders in 
each span are 4 ft. deep, and have a rise of 22 ft. 1 j \ in.; 
they are set at a radius to the soffit of 18.5 ft. 6 in. 

From the extrados there runs parallel with the road- 
way a web girder 2 ft. <> in. deep, which is also continued 
in a vertical line down the face of the pier to connect 
with the curved girder at the springing level ; the spandril 
thus formed has lattice bracing. The bracing between 
the top horizontal and the bottom curved member is 
divided for the most part into (> ft. bays. A roadway 
75 ft. wide is carried on the top <>f this web girder. The 
footpath on each side is 11 ft. wide, leaving 53 ft. for 
the roadway, along which there is laid a tramway. 

The cost of the work was £90,000. This included the 
removal of the old masonry bridge, which was at a 
lower level, and had a greater number of piers; the 
three main arches being only 7<> ft. span, with several 
small side arches. There had therefore been considerable 
interference with the traffic. 






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Sudan Railway Bridges. 

rilHK illustration opposite shows a number of girder 
-^ spans, designed and constructed at the works in 
(Jlasgow for export to the Sudan. Sir William Arrol and 
Company have supplied practically all the bridge-work 
for the railway from the new port of Suakin. on the Red 
Sea, to Khartum, which owes its construction to the 
genius and enterprise of Lord Cromer. The bridges, 
which are constructed for the most part of N girders in 
standard lengths, the spans being 105 ft. and 55 ft., are 
used mostly for crossing rivers, the position of the piers 
and abutments being determined to suit the spans. 

The railway has a total length of Mil miles, and will 
have an important influence in the development of the 
undoubtedly rich agricultural area of the Sudan, as it 
shortens the line of communication to the sea by 900 miles. 
After leaving Suakin it trends northwards, and then ascends 
to the plateau, some 3000 ft. above sea level. Running 
south-west across the desert, a waterless stretch of 50 
'"!, ' lt v reaches the Atbara River at a point about 20 
miles above the junction of that waterway with the .Nile. 



joins the old Khartum-Wady-Halfa military railwa 
»"* a nule north of the Atbara Bridge, and thence th 

trnt M 1 ^ US6d t0 Kbartto - ^ is intended t 

~ ***** lines to develop the resources of the 



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Swing Bridge for Railway Over a Canal 

f\& the opposite page there is an en iving which 
U illustrates a bridge designed, as well as built, by 
Sir William Arrol and Company. Limited, to carry the 
Lanarkshire and Dumbartonshire Railway over the Forth 
and Clyde Canal at Kilbowie. The waterway of the Canal 
is 22 ft. 3 in. in width, but it had to be crossed at an 
angle of 24 deg. : and the line was. moreover, curved in 
opposite directions on entering and leaving the bridge. 
This necessitated a Ion-- bridge, but notwithstanding this 
and the work involved in the turning -car. the bridge 
was completed in five months from the date of the order. 
at a cost of only £6600. The main girders, 17 ft. 6 in. 
deep, are respectively L52 ft. 7 in. and 133 ft. 3 in. long. 
The hack end extends 36 ft. 4 in. from the centre of tin- 
pivot. 

The pivot girder, and those adjoining it. together with 
the main girder on the top of the rollers, are of box 
section, shaped to suit their position, and of specially 
heavy scantlings. The cross-girders at the back end are 
of deep section, as shown in the view, and carry 1^ ( > t0lis 0I 
east-iron kentledge Nocks packed beneath the floor platea 
The roller path and ring of rollers are 19 ft. 4 in "' 
diameter in the centre line. The bridge, which weighs 
416 t.,ns, is swung by hand-gear worked from a small 
platform on the side of the main girders, and can be 
opened in this way in fifty-three seconds or closed O 
sixty-eight seconds. 


















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rilHE Dalginrosa Bridge over the River Earn at Comrie. 
JL shown on the engraving opposite was built in 1904. 
to replace an old masonry bridge with steep approaches 
and of insufficient width to allow two vehicles to pass each 
other. The distance between the abutments of the old 
bridge was 200 ft., and the river piers occupied '2,") per cent. 
of the waterway, causing serious obstruction during Hoods. 
The Local Authorities decided in 1904 to rebuild the 
bridge, and invited firms to submit proposals for its recon- 
struction. The new bridge was to have a width of roadway 
of 20 ft. between the kerbs, with a footway .") ft. wide 
on each side, and a gradient not steeper than I in 30. 
The maximum constructional depth between the surface 

of the road and the flood-water level at the abutments 
was not to exceed 3| ft. As regards load, ordinary road 
traffic was to be provided for, in addition to a traction 
engine drawing two 8£-ton wagons. 

The design submitted by Sir William Arrol and 
Company, Limited, was accepted by the Committee as 
the one which complied with the stringent conditions in 
an economical manner, and was of a pleasing appearance. 
The new bridge is a deck structure, with no obstruction 
to a clear view f t \ w surrounding country. The length 
oi 200 ft. between the abutments is divided into two side 
spans of 55 ft. and a centre span of DO ft., and the new 
piers occupy only 5 per cent, of the waterway. 



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,,„;!.; OF NOVEL DESIGN. 



rhe bridge is a novel type of construction, and is the 
first of its kind constructed in this country. It is of the 
design known as "Constrained Cantilevers," in which the 



cantilevers are continued over the piers and meet in 
the centre of the span, where they are connected by a 
pendulum link. This type was adopted for aesthetic 
reasons, and on account of the small constructional depth 
allowed. The bridge has proved rigid in its construction. 
and agreeably free from vibration. Movements due to 

temperature are provided for at the abutments and in 
the centre of the middle span. 

The river piers were founded by caissons 25h ft. long, 
6 ft. wide, with semicircular ends, and W ft. deep. The 
upper portions of the piers and the abutments are built 
of sandstone. The bridge is carried on four main girders, 
at 6 ft. 4 in. centres, placed under the roadway. They are 
18 in. deep at the abutments, -U ft. at the piers, and 
16 in. at the centre of the middle span. The roadways 
and footpaths are formed of tar concrete, about <> in. thick 
over the crown of buckled plates. The footpaths are 
carried on cantilever brackets fixed on the outer main 
girders, and have an ornamental wrought steel hand-rail. 

During the construction of the bridge, the road traffic 

was provided for by a temporary bridge 153 ft. long and 
13 ft. wide. 






The Manchester Ship Canal Bridges. 

T HE ****** SW P G »'a> ' of a length of 3 5i lni ,es 
necess.tated the construction of . Lrge number of 

St £ V 1C( T mn0f,ati ° n ° f "^ay/and railway 
In he case of railways where the traffic was extensive, 
the In es were deviated ; so that, while the new bridges were 
at a height to give the desire,! clear headway of 75 ft 
above the water surface, convenient approach gradients could 
be arranged. For roadways, and also for railways with a 
moderate volume of traffic, swing bridges were constructed. 

«■ w" DatUral that a finn of the experience of 
Bit Wilham Arrol and Company, Limited, .should take 

* ^-ge part in this bridge -building work, and of the 
eight large swing bridges, six were constructed bv the 
&rm ; while of the heavier railway bridges, six also' were 
built by them. As typical of the latter, we illustrate 
"ii the next page one of the principal railway structures, 
carrying the main line of the London and North-Western 
Railway. This bridge, it will be seen, was built on a 
heavy skew. The girders over the canal are of 298 ft. 
111 length, and 36 ft. in depth at the centre, tapering to 
24 ft. at the ends. 

The opening bridges were built to turn on a roller 
path on one bank, so as to leave the canal without 
obstruction. The roller ring of one of the bridges is 
illustrated on page 135. 

1 See Enoimikeino, toL Ivii., page !)7. 



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OPENING BRIDGES ON MANCHESTER SHIP CANAL. 

The accompanying Table shows the principal dimensions 
of the swing bridges built :— 





Name of 

Bridge. 


Span. 


Width 

of Roail. 


Length 

- -t 

Long 

Ann. 


Length 

of 
Short 
Arm. 


Depth of 
Main < rirdei - 

at ( 'flit i e 

over Angles. 


Numbei 

of 

Rollers, 


1 li.iiiic • 

oi 

Roll,., 

Circle. 


Weight 


( Hd Quay, Runcorn 


ft. 

120 


ft. 

20 


ft. in. 
l«59 I ,, 


ft. in. 
•Hi Id,", 


ft. in. 
28 


60 


it. in. 

22 11 


tons 
650 


Moore Lane 


1 20 


25 


140 


'AS 


27 84 


64 


27 LOj 


790 


Stagg Inn 


120 


23 


140 


98 


27 8 


64 


27 10 


790 


Northwich Road ... 


1 20 


36 


US 


100 


30 


60 


38 9 


1350 


Knutsford Road .. 


1 20 


36 


14S 


LOO 


30 


GO 


38 9 


1 351 ' 


Barton Bridge 


90 


25 


111 


si 


26 


64 


27 LOJ 


640 



The point of interest in connection with these various 
swing bridges is the method of turning them. Secured to 
the main structure through four cross girders is an annular 
girder, which, in the case of the heaviest bridge, was built 
up of L8 cast-iron segments, the upper flange being 3 ft. 
3 in. wide, and the lower 2 ft. 10 in., strengthened by 
diaphragm plates. This annular girder has an outside 
radius of 15 ft. 5 in, and was built in concentric webs, 
each 1 ft. 10 in. in depth. A series of radial beams connects 
the annular girder with the centre bearing resting on the 
pivot on which the bridge rotates. The annular girder 
rests upon rollers, which again bear upon a fixed circular 
track of similar construction to the annular girder. As 
shown in the illustration, there are sixty rollers, conical in 
to™ to suit the radii. A bolt passing through each 
roller forms an axle, and is connected with a live ring on 
otn sides; gun -metal washers are placed between the 
l ^ss ol the roller and the web of the live ,W 




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Blackfriars Bridge, London, 

rpHE Blackfriars Bridge across the Thames 1 has a length 
-*- between abutments of 922 ft,, and is divided into five 
spans, varying from 155 ft. to 185 ft. Each span is formed 
of arched ribs, spaced about 10 ft. centres, supporting the 
roadway girders above the level of the crown of the arch. 

In 1906 it was decided to proceed with the widening 
of the bridge from 75 ft. to 105 ft. between the parapets, 
to enable a double line of tramway to be laid across the 
bridge to connect the lines on the south side of the river 
with those on the Embankment. The contract for this 
work was let in 1907 to Sir William Arrol and Company, 
Limited, who undertook to complete it within three years. 

The operation of widening the bridge involved the 
lengthening of the abutments and piers, with their founda- 
tions, in the line of the river, the transfer of the existing 
face ribs on the west side, with their cast-iron spandrils 
and hand-rail, along the extended piers 30 ft. further west. 
and the building of three new ribs between the older 
portion of the bridge and the outer rib in its new position. 

In all the spans, except that next the north abut- 
ment, a clear passage for navigation had to be maintained 
throughout the progress of the work. 

Across the north span and extending westwards, a 
timber staging was built, which served as a platform for 
receiving, handling, and storing material, and the new ribs 

i See Engineer.^, vol. lxxxiii., pages 75 and 853; vol. lxxxvi., page 251; 
vol. Ixxxvii., pa^e .'510. 



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•AisSONS FOB LENGTHENING THE PIERS. 



nt this span were erected on trestles resting on the plat- 
form. In the case of the remaining spans a timber staging 
as built round the site of each of the new foundations, 
as shown in one of the views facing this page. At the 
south abutment a somewhat similar staging was placed 
round the cofferdam used there for foundation work. 

The sinking of the caissons at the north abutment was 
attended with considerable risk, owing to the adjacence 
of the Metropolitan District Railway tunnel, the old 
abutments, and the Embankment walls. The new caissons 
were carried considerably lower than the adjoining old 
foundations. When the three caissons forming the new 
abutment foundations were sunk and tilled with concrete 
they were loaded with about 3000 tons of rails to con- 

solidate the foundations and obviate any settlement after 

the bridge is completed. All the operations at the 
abutment were entirely successful, and were carried out 
without disturbance to any of the old works. 

The foundations of t lie new part of each pier consisted 
of a caisson, shaped in plan with a cut- water point, and 
with a recess to fit the point of the existing caisson, 
as shown in the upper view on the opposite page. The 
caissons were built over their final position, and sunk by 
the pneumatic process in a manner similar to that adopted 
at the Clyde and Wear Bridges already described. 

The erection of the steelwork in the north span 
presented no difficulty, as it was built in situ on the 
temporary staging. No scaffolding was permitted in the 
other spans, and the work of removing the existing face 
ribs was carried out by means of an overhead traveller. 
as shown in the engravings on the three following pages. 
It moved on rails laid on the top of the new portion 
°f each pier at right angles to the centre line of the 








EKKCTION <»K NEW STEEL WORK. 



136 r 



bridge. From the overhead traveller then- were suspended 
hangers, each of which was provided with a screw at the 
top, while the lower end was secured to the rib about to 

be shifted. 




Rib just Launched, showing Temporary Girders Used for Steadying 

Rib during Launching. 






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When these preparations for lifting were completed, 
the floor between the face rib and the adjoining ordinary 
rib was removed. Cross-staging girders had previously 
been put in place and fixed to the face rib at one 

end. These girders were meantime held up below the 
old portion of the bridge, and passed through a special 



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SAFEGUARDS. 



stirrup bearing attached to one of the old ribs. The rii 
was raised from its bearings at the skewbacks by 
tightening up the screws on the top of the hangers. 

This operation was performed with extreme care, to 
ensure that the weight would be distributed equally 
upon the several hangers attached to the rib. When the 
rib was clear of the skewbacks. the overhead traveller 
was moved forward 130 ft. in short stages by means of a 
tackle operated from cranes on the staging. To prevent 
the rib swinging on the hangers, it was controlled by 
means of screws secured on the cross-st airing erirders 
between the old ribs. When the face rib was over its 
new position it was lowered to its correct level, and white 
or other metal run in between the abutting faces at the 
piers. The cross-staging girders were securely fixed to 
the face rib and the next old rib, spanning the distance 
between them and forming supports upon which to erect 
the three new ribs. The floor girders and cross frames 
were afterwards built. The heaviest rib moved weighed 
150 tons, and the traveller <J0 tons. 

Ihe face ribs of the respective spans were moved to 
the new position in the order which would produce least 
unbalanced thrust on the new portions of the piers, and 
the building of other portions of the superstructure was 
strictly limited to certain points for similar reasons. 
















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Viaduct over Walney Channel at 

Barrow=in=Furness. 



TXTITHIN recent years, the Isle of Walney, which lies 
* seaward of the town of Barrow-in-Furness, and is 

separated from it by a channel about a quarter of a mile 
wide, has become a residential district. The consequent 
growth of traffic across the channel has necessitated the 
superseding of the ferry steamer by a viaduct 1 designed 
by Messrs. Baker and Hurtzig, Westminster. 

The total length of the viaduct between abutments is 
1125 ft. There are eight fixed spans varying from 83 ft. 
to 118 ft. in length, and one opening span of the rolling- 
lift type, which gives a clear passage of 120 ft. for navi- 
gation. The roadway, on which there is a double line of 
tramway, is 31 ft. 4 in. wide, and the footpaths 9 ft. 4 in. 
All the piers are formed of pairs of cylinders, partly of 
steel and partly of cast iron, filled with concrete and 
bound together by a capsill girder at the top. 

Each fixed span consists of two main girders of lattice 
construction, placed 31 ft. apart. They are connected by 
the roadway cross girders, which are riveted to the top of 
the vertical posts. Underneath these cross members the 
main girders are tied together by suitable diagonal bracing. 
The longitudinal stringers are placed over the cross 
girders, and support jack arches of concrete on which 



i See 1VN..INEEHING. \-l. IxxxvL, pages 65, 69, 172, and 231. 



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THE OPENING SPAN. 



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the wood block roadway Moor is laid. The t'<»> twaya rest 
on cantilever brackets riveted to the outside of the main 
irders. 

The opening span is of the Scherzer type, with two 
leaves of plate-web construction, and with a clear opening 
of 120 ft. It is the largest span of this type in this 
country. Several improvements on the earlier rolling-lift 

bridges are embodied in it. In previous bridges the 
segments of the opening leaves were rolled along the fixed 
track girders by means of horizontal struts operated by 
machinery placed on the adjoining fixed spans. One end 
of each strut was fixed to a connection at the centre of 
the rolling segment, and the other end was geared to the 
machinery. In the Walney Bridge these struts are dis- 
pensed with, and the machinery placed direct on the 
opening span leaves. Alongside the track girders there 
are frames supporting fixed racks, into each of which is 
geared a large pinion wheel, keyed to a shaft passing 
through the centre of the rolling segment, or "the centre 
of rotation." When these shafts are actuated by the 
operating machinery, placed between the main girders of 
each leaf, the span is opened or closed. Electric power 
is used throughout, but hand gear, which may be operated 
from the permanent dolphin, is also provided. 

All the opening and signalling operations are con- 
trolled from a cabin on the Walney side of the opening 
span The controller levers are so interlocked that all 
^gnalhng and opening operations can only be effected in 
-per sequence. The time required to open the bridge 

8 min r I SeC ° DdS ' and t0 dose * to river traffic, 
unites i seconds, including all operations. Two 25 

pCI^ T ^ Pr ° vided for "P-kB «* « 

timber dolphins were constructed at each 






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THE ERECTION OF THE BRIDGE 



side to protect the piers and gizderwork of the opening 
span from damage by shipping. 

On the Barrow .side of the bridge the abutments rest 
on clay, which was sufficiently stiff to enable excavations to 
be carried out with light timbering. Loose running sand 
was encountered on the site of the Walnev abutment and 
necessitated the adoption of a full tide cofferdam. 

For the erection of the bridge a staging was built 
across the channel on the line of the bridge. It consisted 
<>f pile trestles spaced about 10 ft. apart, supporting 
the longitudinal timbers and bogie tracks on which a 
travelling crane was placed. The cylinders of the piers 
were lowered to the river bed from the staging and were 
sunk under pneumatic pressure to their ultimate depth. 
The lower rings of the cylinders are of steel, and the upper 
rings of cast iron. During sinking, the cast-iron rings 
were not subjected to air pressure : the inner ring of con- 
crete always extended a foot above the roof of the working 
chamber. The lower end of the working shaft was con- 
nected to this roof of concrete, and to the upper end the 
usual air locks were attached in a manner similar to that 
described on page 18. 

The main girders of the fixed spans were erected in 

their final position from the temporary staging. In order 

to keep a clear waterway there was no staging in the 

centre channel, and the opening span was erected in an 

upright position. When nearly completed, the leaves were 

lowered to the closed position by the hand gear, in order 

that the last lengths, with the connections between the 

leaves, might be inserted. At the same time the balancing 

01 the leaves was adjusted and the electrical operating 
gear installed. l 



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Such a condition has long ago been 



The Design of Workshops. 

mHERE are still extant in this country a sufficient 
number and variety of examples of old engineering 
shops to establish the remarkable development that has 
taken place during the past fifteen or twenty years in 
the design of factory buildings. The old shops, with 
their masonry walls and timber-trussed roofs, afforded 
splendid protection from weather, but were as well — or as 
ill-lighted — to quote a proprietor of such a shop — "at 
midnight on the 21st of December as at mid-day on the 
21st of June." 
recognised as inimical to efficient and economical manu- 
facture. The demand to-day is for complete glazing, so 
that there may be the minimum loss of natural light, 
with adequate weather protection. 

It is now many years since Sir William Arrol and 
Company, Limited, built their first workshop on those 
lines; and since then they have, as the following pages 
suggest, reconstructed many old works and erected many 
admirably planned new establishments. 

The modern factory building may not be any more 
beautiful than the old structures when viewed externally; 
but the interior is, as a rule, pleasing to the eye. The 
light steel truss has taken the place of heavy timber 
work, giving an impression of sufficient strength com- 
bined with a general sense of lightness and fitness of 
design. The lattice columns and girders suggest that 



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140 



THK CHIKK CONSIDERATIONS IN DESIGH 



the material has been used in a way that takes full advan- 
tage of its qualities, while the long-drawn bays bespeak 
familiarity with constructional steelwork and studied 
economy in design and arrangement. 

The first object in design is, of course, to build a 
shop suited to the business. Nowadays this practically 
amounts to a steel structure, to all intents and purposes 
independent of its surrounding walls. The width and 
length of bavs are settled by the size and amount of 
work : the height depends on the size of work and the 
use to which cranes will be put : and the form of roof 
is chosen with due regard to lighting, ventilation. &c. 
The walls — of brick, masonry, galvanised iron, or weather- 
boarding — serve as protection to the contents against 
weather and depredation. Brick work is now being pre- 
ferred for the walls in preference to the corrugated iron 
of earlier buildings, because the maintenance charges are 
lower, and the temperature within is higher in winter and 
lower in summer. 

One of the chief considerations to be taken into 
account in designing details of steel work of the present 
• lay structure has reference to crane-power. Shops for 
small work present but few difficulties. Stiffness to resist 
wind pressure can be easily arranged for, while provision 
for lighting, ventilation, shafting, and good floors are 
important but simple desiderata. With large shops, in 
which crane loads of from 50 to 150 tons have to be 
provided for, important problems have to be solved, which, 
^ indicated in the Appendix, demand experience and 
-are. Columns which have to support the roof and crane, 
■M also the structure as a whole, must be stiff enough 
" wjjt all strains due to the use of cranes and shafting. 
action to those due to external agencies, such a> 



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bESIDERATA AND THEIR REALISATION. 



141 



wind and snow. These points have been subjects of 
careful investigation by Sir William Arrol and Company, 
Limited. There are, for instance, the forces on the 
structure of a shop due to cranes ; the horizontal 
stresses produced in a building by the sudden appli- 
cation of the brakes of a crane or cranes, carrying a 
heavy load ; the effect of the cross-travel of the crab : 
the stresses when cranes are used for dragging things 
along the shop-floor ; the stiffness of columns and girders 
to withstand stresses due to combinations of loads such 
as those involved by overhead and jib-cranes working 
in close proximity to each other ; and the allowances 
necessary for expansion. 

These, stated at random, are only a few of the con- 
siderations involved in the design of workshops. On 
the four succeeding pages there is a list of the principal 
workshops built by Sir William Arrol and Company, 
Limited, and following it are brief descriptions and 
illustrations of typical buildings. In the Appendix are 
standard specifications, with other data and formulae, 
which will assist the reader in appreciating the high 
efficiency aimed at in the buildings designed and con- 
structed by Sir William Arrol and Company, Limited. 



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John Brown and Co., Ltd., Clydebank. 

niHKKK lias been a Long association between Sir 
A William Arrol and Company, Limited, and the 
Clydebank Shipbuilding Yard. 1 one of the foremost naval 
construction establishments in this country. In that yard 
there has been built a long series of powerful warships and 
record-breaking Atlantic liners. The wealth of experience, 
alike in management and manufacturing methods, is indi- 
cated by the fact that the list of warships built, so tar. 

terminates with the powerful battleship "Hindustan" and 
the greatest cruiser yet designed, the "Inflexible," which 
combines -with an unexampled armament of eight L2-m. 
guns a speed of 23 knots; while the latest of the 
merchant vessels is the Cunard liner " Lusitania, of 
32.500 tons, also to attain a speed of 25 knots. 

Many of the buildings at the Clydebank Works have 
been designed and constructed bv Sir William Arrol and 
Company, Limited. The shop most recently completed is 
the erecting shop, where the immense turbines for the 
new Cunard liners and the cruiser have been built. 
This shop is 241 ft. long and 129 ft, wide, with a height 
of 72 ft., and the structural details have been arranged 
to accommodate in each bay two cranes with a combined 
lifting capacity of 120 tons. In this shop the firm have 
undertaken probably more turbine machinery than any 
other firm, the total horse-power of such engines, finished 

1 See Engineering, vol. lxxii., pages 242, 275. 






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MOULDING LOFT \M' SAW MILL 



or in course of construction in January. 1907. being 

129,000 horse-power. 

Two other striking buildings are illustrated on the 
opposite page. The moulding loft, which is 376 ft. long 
ami 53 ft. wide, is one of the finest buildings of the 
character yet completed, being particularly well lighted. 
On the floor of this building the lines of the ships to 
be built are drawn full size for the construction of the 
templates which are subsequently used for the machining 
of frames, beams, plates, etc.. to bo worked into the ships. 

The other building illustrated is the saw-mill. 200 ft. 
long and 132 ft. wide, with a height of 52 ft. The 
engraving indicates the satisfactory character of the 
design. 

At the Sheffield Works of the Company, Sir William 
Arrol and Company, Limited, have erected a workshop 
262 ft. long and 256 ft. in width, with a height of 63 ft. 
The largest of the seven overhead cranes carried by the 
columns of the building lifts a load of 75 tons. 










I 






William Beardmore and Co., Ltd., 

Dalmuir. 



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ONE of the largest, and at the .same time one of the 
finest, naval construction works in this country is 
the new establishment of Messrs. William Beardmore and 
Co., Ltd., at Dalmuir. 1 As those responsible for the 
planning of the establishment had, to use an historical 
phrase, a "clean slate," there was no hindrance to the 
realisation of the best possible scheme to meet modern 
conditions. There was, initially, a clear conception of the 
full extent of the requirements : it was intended that the 
best of naval and merchant work should be undertaken. 
At the same time it was decided that every approved 
system of modern manufacture should be adopted, with 
a view not only of dealing with the work in the most 
efficient manner, but also of ensuring that the highest 
degree of economy should be realised. 

The new works have an area of about 90 acres, and 
a river frontage of nearly a mile— to be exact. 4920 ft. 
The shipbuilding berths have been arranged to take vessels 
up to 1000 ft. in length and over 100 ft. beam. 

One of the most interesting problems in connection 
with the equipment of the shipbuilding yard was the 
arrangement of cranes for lifting material on board vessels 
™ course of construction. Time was when ordinary shear- 

1 See Engineering, vol. lxxviii., page 155. 






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152 



SHIPBUILDING BERTH. 



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legs, and other temporary devices, were sufficient for 

most purposes: but with the great advance in the size 
of ships, and the increased weight of plates and angles 
worked into their structure, it has become necessary, in 
•der to economise time, to provide more perfect crane 
appliances, for the crux of success in naval and merchant 
shipbuilding now is rapid construction. 

The arrangement of the principal berth for the con- 
struction of battleships is illustrated by the longitudinal 

plan and cross-sections on the opposite page, and by an 
engraving on page 151, which shows also His Majesty's 
battleship "Agamemnon." the largest battleship yet built 
on the Clyde. The berth structure was designed and 
erected by Sir William Arrol and Company, Limited. 

It will be noted that there are on each side of the 
berth four jib travelling or walking cranes, capable of 
lifting 5 tons, and having an overhead reach of 30 ft. 
Each of these cranes can travel the full length of the 
berth on rails supported by the vertical members of the 
building, and they may be congregated, if necessary, to 
deal with exceptionally heavy loads. At the same time 
there is a high-speed travelling crane stretching from one 
side to the other of the building berth, and capable of 
lifting 15 tons. This crane is specially useful for lifting 
weights into the centre line of the ship, while the jib 
cranes are at the disposal of the several plater or fitter 
squads engaged on the bottom or side shell plating. 

Eight squads can be at work on a ship, each having 
J > crane for dealing with material. The angle and plat.' 
trucks pass down each side of the berth, between the legs 
of the vertical members of the structure, as shown in the 
cross-sections, so that there is the minimum of obstruction : 
the empty wagons return on an outside track. 





















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EXOIXI VND BOILER WORKS 



berth is 750 ft. loner, 



The superstructure over the 
135 ft. wide, and L50 ft. high at the end nearesl the 
river The roofing is not glazed. The vertical members 
f t | l( . s tee] w.»rk are carried on concrete foundations. 
Beavy timber piling has been put in throughout the 
length of the berths, with special rows, having suitable 



caps, urn 



ler the keel blocks, under the position occupied 




William Beardmore and Company's Boiler Works. 

by the ways, and under the bilge blocks. The piling is 
very close near to the water's edge, where there will be 
the maximum thrust when the stern of the vessel first 
floats in the process of launching. 

The boiler and engine shops were also designed and 
constructed by Sir William Am.l and Company.' Limited, 
and of these engravings are published on this and opposite 
pages. The building, wind, includes both shops, is probably 
one ot the finest yet constnu-to.l. The lei.-tl. is 720 ft, 
and the width 323 ft, in five bays, so that the total area 



4 



L1 









BOILER WORKS. 




is nearly 5i acres. The bays extend from north to south, 
and the northern part of all live is utilised for boiler 
construction: while the southern part is arranged for the 
building of marine and other machinery. Here there has 
been erected the first large producer-gas engine completed 

lor marine purposes. 

All the materials for engines and boilers enter at the 
centre of the shops, those for engines being delivered to 
the south side of the line, and those for boilers to the 
north side. The machines in both departments are so 
disposed that the units during the process of manufacture 
travel from the delivery line towards the extreme end of 

4. 

the works. The completed engine leaves at the south end, 
and the boilers at the north end. on rails communicating 
with the fitting-out basin. 

The bays range in width from 80 ft. to 50 ft., and the 
height in each case is 75 ft. The construction is very well 
shown in the engraving on the two preceding pages, and the 

general effect, with such an area of glazing, is particularly 
striking. In the shop there are thirteen cranes, all of 
the electric type, ranging from 60 tons downwards. Two 
of the uo-ton cranes can be yoked together to carry 
120 tons, the columns and girders being made to suit 
the weight. 

Suggestion is afforded of the immense height of the 
roof by the engraving on the opposite page, illustrating the 
riveting of the shell of a boiler in this department. 





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Vickers Sons and Maxim, Ltd. 



rilHIS firm have not only an armour-plate and gun 
-*- factory at Sheffield. 1 but a great arsenal at Barrow- 
in-Furness, 2 where there are constructed merchant steamers 
and warships, and all types of marine machinery, in 
addition to the extensive mountings for manipulating 
heavy guns and the projectiles for the same.' 

Besides completing for war many of the most powerful 
British warships, including the battleships "Dominion" 
and ■•Vengeance/ 5 and a greater variety of other ships 
than almost any other firm, the Vickers have produced 
many lighting ships for foreign navies, and have helped 

to establish British credit as the greatest naval con- 
struction country in the world. Mention may be made 
of Togo's triumphant flagship, the "Mikasa" ; the later 
Japanese battleship, the "Katori" ; the battleship-cruiser 
"Rurik," for Russia; a battleship for Brazil, which promises 
to be equal to the best; and other fighting ships for 
Brazil, Chili. Peru, and other Powers. 



It 



Sir \Villi aill Arrol and Company. Limited, have bui 
for the Vickers one or two notable workshops, includii 
the ,,-on foundry, which is illustrated on the opposite page 
Ihis is 264 ft. long and L50 ft. wide, the height of roof 



1 See Engineering, *.]. briv., pages m, 
, " l > 703, 729, 760, 791. 

' // "'"'- vol. lxxi,., pages 169, 183, 215. 
lh " / - vol. l.wii.. page n 



130, 457. 521, 555, 583, 607, 6 










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Vickers' Foundry for Marine Work at Barrow in I'urness. 



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Vickers* foundry for Ordnance at Barrow = in Furness 



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being 55 ft. There are fitted in it two 45-ton cranes and 
one of 25 tons, which suggest the massive character of the 
w ,„. k turned out. In one bay marine castings are made, 
in the other ordnance parts are produced. 




One of VickerV Ordnance Workshops. 



Another of the Arrol shops is that built in 1901, and 
illustrated on this page. Tins building is 250 ft. long, 
17.") ft. wide and lias a height of 30 ft. It is. it will be 
noted, devoted to light ordnance work. 







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Shipbuilding Berth Equipment 

at Belfast. 












• 



FT1HE firm of Messrs. Harland and Wolff have maintained 
-*- a high reputation for enterprise in the equipment of 
their engine shops and shipbuilding yards at Belfast, and 
the developments of science and its practical adaptation 
to the construction of ships have been constantly kept in 
view by the firm to enable them to retain their prominent 
place among the builders of ocean liners. The keen rivalry 
on the Atlantic has resulted in the White Star Line 
placing an order with Messrs. Harland and Wolff for 
two immense steamers to be named the " Gigantic " and 
" Titanic," and as a consequence large additions have been 
made to the yard at Belfast to enable the firm to under- 
take the work. The principal addition has been a double 
gantry in the north yard, complete with cranes to deal 
with the erection and riveting of the hull and decks. 1 The 
new structure occupies the former site of three building 
slips, and is illustrated on the two following pages. 

The structure, which has a total length of 840 ft., 
consists of three rows of towers placed 80 ft. apart 
longitudinally, and 121 ft. transversely. These towers 
support longitudinal girders tied together transversely at 
their tops, which in their turn carry a track over the 
centre row of towers, and on it a cantilever crane may 
travel the whole length of the structure. 






i See Enginbbmng, vol. lxxxv., page 791. 



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OVERHEAD TRAVELLING CRANES 



A track is provided on the top of the longitudinal girders 
to carry travelling frames, which span across each berth. 
Each travelling frame contains two 10-ton travelling cranes. 

Another track is provided at the bottom of the longitudinal 
girders to carry 5-ton walking cranes. The rail level of 
the central track for the cantilever crane is 176 ft. above 
the ground level at the after end of the berths; the rail 
level for the travelling frames is 148 ft., and for the walkin 



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cranes 118 ft. above ground level. 



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Section Shoving; Overhead Travelling Cranes. 

The cantilever crane is capable of lifting 3 tons at a 
radius of 135 ft., and 5 tons at a radius of 65 ft., and has 
lifting, racking, slewing, and travelling motions. It com- 
mands a length of over 1050 ft. and a width of '270 ft., and 
can lift or deposit material at any point within this area. 

The six travelling frames, provided with two 10-ton 

cranes within them, are for carrvinir the riveting machines. 

Lhe internal travelling cranes have a longitudinal travel 

of about 35 ft. without the necessity of moving the frames. 

The frames at the after end of the berths have lifting 

eyes to deal with stern frames, etc., weighing up to 40 tons 
each. 

The ten walking cranes are designed to lift 5 tons at a 



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FACILITIES FOR RIVETING THE SHIPS. 



radius of 53 ft. and have lifting, slewing, and travelling 

motions fitted to them. 

The inside i'm'^ of all towers are fitted with a special 

arrangement to carry portable riveting or building platforms 
at any level and at any angle to suit the line of plating. 
Fixed sloping gangways are provided at the forward end 
of the berths, and are arranged to pass through the towers. 
Easy access is provided by them to any level up to the 
underside of the longitudinal girders. A complete system of 
stairs and gangways is provided throughout the structure so 
that communication may be had to any part of the structure 
oi- to the cranes. 

The cranes, which were supplied by Messrs. Stothert 
and Pitt, of Bath, as sub-contractors, are operated electri- 
cally, current being supplied from the main power station, 
and their collective power is 1600 horse-power. 

The whole equipment was undertaken by Sir William 
Arrol and Company, Limited, and was designed by their 
engineering staff to the requirements of Messrs. Harland 
and Wolff. 














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Tranmere Bay Development Co., Ltd., 

Birkenhead. 



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rpHLS Company is now laving down what will be one 
-* of the largest shipbuilding and engineering establish- 
ments in the country. 

The works are practically complete, and will have 
facilities for undertaking the largest class of vessels and 
machinery, including turbines. 

The new buildings for the establishment have been 
designed, and are being built, by Sir William Arrol 
and Company, Limited. 

The engine erecting shop is 1075 ft. long and 
77 ft. wide, with a height between the floor and the 
inside of the roof of 74 ft. There will be in this building 
70-ton cranes, and the constructive steel work is so 
designed that two cranes close together may traverse 
the whole length of the shop with a load of 140 
tons. This new shop is shown in course of erection on 

page 163. 

At one side of the main shop there is a building 
615 ft, long and 42 ft. 6 in. wide, with 35-ton cranes ; and 
on the other a machine shop 525 ft. long and of the 
same width, also with 35-ton cranes. 

The new boiler shop has a main bay 500 ft, long 
and 130 ft, wide, and 69 ft. high, with two 70-ton cranes, 
the structural steel work again being designed to lift and 



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1 62 



an IMMENSE BOILER SHOP. 



traverse a Load of L40 tons. On <>.,<> side of this building 
there is a bay 420 ft. Long and 50 ft. wide, and of a height 

of 38 ft. 

In addition, Sir William Arrol and Company, Limited, 

are building a smith's shop 270 ft long and 40 ft. wide, 
and several other buildings. 



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The 



Fairfield Shipbuilding and Engineering 

Company, Limited, Govan. 



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IT would be difficult to find in the extensive establish- 
ment of this well-known Company a workshop of 
primary importance with which Sir William Arrol and 
Company, Limited, have not been associated. 1 They 
designed and built the moulding loft of 275 ft. in 
length, where the lines of some of the best ships now 
afloat were laid down, including the immense battleship 
"Commonwealth," the 25-knot cruiser "Indomitable" and 
the new Canadian high-speed Mail steamers 'Empress 
of Britain" and "Empress of Ireland." They constructed 
the joiners" shop, where some of the finest floating 
hotels have had their artistic furnishing completed. 
They erected engine and boiler shops, where powerful 
reciprocating and turbine machinerv has been constructed : 
and brass foundries, fitting" shops, mechanics' shops, smithies 
and brass finishers' departments, and others, have all been 
reconstructed by them within the past ten years. 

As typical of the work done, we give engravings of 
the engine-erecting shop and the boiler shop. The former 
is illustrated on the opposite page. This new shop has a 
length of 291 ft. and a width of 55 ft, and the height to 
rail level is 50 ft,, and to the roof ties 58 ft. The travelling 

1 See Engikebeing, vol. 1„ pages 336, 393, 485, 599, 687. 













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NOTABLE TURBINE MACHINERY. 



cranes range in capacity from 50 tons downwards. Tn 
tl.is shop there have been constructed not only triple- 
expansion engines, ranging up to 15,000 horse-power, but 
many sets of Parsons turbine machinery for yachts, channel 
steamers, ocean liners, and high-speed cruisers. Amongst 
the turbine installations, prominence must he given to 
the 41,000 horse-power set for the four-screw cruiser 
" Indomitable," the 23,500 horse-power installation for the 
new battleship " Bellerophon," and turbines of 14. .loo 
horse - power for two high - speed steamers for service 
between Marseilles and Egypt, to inaugurate a new British 

service in the Mediterranean. 

The new boiler shop is illustrated on the opposite page. 
Here, not only are the largest of the cylindrical boilers 
constructed, but water-tube boilers for modern warships 
are completed. The length of the shop is 'M)i) ft., the 
width 60 ft., and the height 55 ft. () in. There is a tine 

■ 

installation of cranes. 



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The 



Coventry Ordnance Works, Glasgow. 



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rpilE new Coventry Ordnance Works at Scotstoun, 
^ Glasgow, 1 have been designed and built by Sir 
William Arrol and Company, Limited, for the manu- 
facture of gnu mountings for warships constructed by 
Messrs. Cammell, Laird and Co., Ltd.. of Birkenhead ; 
Messrs. John Brown and Co., Ltd., of Clydebank; and the 
Fairfield Shipbuilding and Engineering Company, Limited, 
Govan. These three shipbuilding companies are joint 
partners in this undertaking. 

The works rover an area of 20 acres, and include 
two fine workshops, each having a length of 675 ft., and 
a collective width of 134 ft., the height being 63 ft. 

In the larger bay, which we illustrate on the opposite 
page, there is to be an overhead traveller to carry a load of 
LOO tons, and others of from 60 tons capacity downward. 
The crane rail level is 44 ft. above the floor, so that 
the loads carried may not only be heavy but of large 
bulk. In the same bay but at a lower level, there are 
rails for a series of 10-ton travellers for the ordinary shop 
work. An unusual feature in this bay is that both crane 
runways are the same span, so that the lighter cranes 
may be lifted to the higher level and worked there. 
The difficult problem of providing two runways in the 
same hay. and of the same span, at different levels was 
satisfactorily solved, as shown in the illustration. 

engineering, \<<\. Ixxxiii., page 571 



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170 



SATISFACTORY DESIGNS: RAPID CONSTRUCTION. 



Parallel with these shops is a gantry of corresponding 
length— namely, 675 ft., with a span of 87 ft,, and a 
height above the surface level of 50 ft. This gantry is 
for the accommodation of 100-ton and lighter cranes tor 
the loading and discharging of gun mountings. 

The design of roofing adopted in this case is the 
"umbrella" or " ridge-and-furrow " type, supported in the 
ridge, and entirely covered with glass. The roof is carried 
on cross-girders at 2!) ft. centres, which rest upon columns 
with deep foundations. The advantage of this system of 
roof construction is that the building will be more stable 
than one of the ordinary ridged roof type, under the 
severe racking stresses due to the heavy high -speed 

travelling cranes. 

The whole of the constructional steel work of these 
large shops, requiring the use of 2500 tons of steel, was 

completed within six months of the date of the placing 
of the order. Of this time sixteen weeks sufficed for 
the erection of the structure — a proof of the splendid 
organisation and suitability of the manufacturing and 
erecting plant employed by the Company. 











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Glenfield and Kennedy, Ltd., 

Kilmarnock. 



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HIS firm, which has a high repute for hydraulic 
machinery, water meters, and foundry work gene- 



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rally, has had two foundries constructed by Sir William 
Arrol and Company, Limited, one of which is illustrated 
on this page. The length is 251 ft. and the width 137 ft., 
with a height of 44 ft. There has also been erected a 
foundry for light work. This is of the same length, of 
greater width, and of a height of 67 ft. 



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The Wallsend Slipway and Engineering 
Company, Limited, Wallsend=on=Tyne. 



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EW engineering establishments in this country, or 



even abroad, have experienced so rapid an advance, 
alike in volume and quality of work done as that 
of the Wallsend Slipway and Engineering Company 
since Mr. Andrew Laing became associated with the 
establishment. 

Previously the largest set of machinery completed was 
of 4. (>(>() horse-power, and the average output of machinery 
per annum was 20, 000 indicated horse - power, with a 
maximum of 40.000 indicated horse-power. During the 
past five years the average has been 67,000 horse-power 
with a maximum of 115,000 indicated horse-power. The 
largest set of machinery— that for the 25-knot Cunard 
liner " Mauretania "— is of 70,000 horse-power. At the 
same time the firm have been entrusted with machinery 
for several warships, including the turbines for the new- 
battleship "Superb," of 23,000 shaft horse-power. Thus 
the firm is in the front rank in connection with turbine 
machinery for warships and merchantmen. 

The new buildings have been designed and con- 
structed by Sir William Arrol and Company. Limited. 
and were, as a rule, built outside and around the old 
shops, so as to involve the minimum of inconvenience 
during the process of erection. We illustrate two of the 






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174 



A LARGE BOILER SHOP. 



new buildings-the engine-erecting shop on the preceding 

pa-e, and the boiler shop on the opposite page. 

" The erecting shop, in which the immense turbines for 
the " Mauretania " were completed, has a length of 570 ft., 
but is built so that when required an extension ran easily 
be made. The width is 60 ft., and the height G5 ft. In 
this shop there are, as shewn in the engraving, two cranes 
of (>5 tons and one of 30 tons capacity. 

The boiler shop, which is illustrated on the opposite 
page, has a length of 330 ft, a width of 75 ft., and a height 
of 70 ft. A proof of the capacity of this shop is afforded 
by the fact that the output of marine boilers is almost 
one per week. As to its sufficiency alike in breadth and 
height, there is the fact that the whole of the 25 boilers 
for the "Mauretania'* were erected in this shop, and their 
uptakes, steam pipes, and platforms completed, as shown 
in our engraving. 1 In this wav all the parts were fitted 
together, so that when marked and removed to the ship 
the final fitting and riveting was most expeditiously done. 



1 See K\(ii.\'Ki-:]!i.\«;, vol. Ixxxii., page 349. 








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Scotts' Shipbuilding and Engineering 



Company, Ltd., Q 



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ONE of the earliest shops constructed by the Company 
was for the Scotts 5 Shipbuilding and Engineering 

Company. Ltd.. of Greenock, and the illustration on the 
opposite page is. from this point of view, of special 

interest. 

In this shop some of the finest modern marine 
machinery has been completed, including engines of 27,000 
indicated horse- power, for the 24 -knot armoured cruiser 
"Defence." This is the latest of the long succession of 

naval contracts carried out by the Scotts" Company, whose 

association with the Admiralty began as far back as L803, 
when they built the sloop of war "The Prince of Wales," 
succeeded by the first Clyde-built steam frigate and by 
many notable warships. 

Indeed, Scotts' Company are almost unique, as for two 

centuries they have taken a prominent part in the 

development of shipbuilding and marine engineering; and 
the works have been carried on by a succession of Scotts 
in the direct line of descent, the present managing 
directors belonging to the sixth generation. 

1 See ExoiKi bring, vol. IxxxL, ] 171. 










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WHEN the story of the development of the torpedo 
bout and of light high-speed machinery is written. 
the name of Yarrow will occupy a prominent place. The 
firm haw devoted a large amount of time and money to the 
solving of problems associated with the design of such craft. 

In the first place, they tackled the question of the 
tensile strength of the material used, with the result that 
they were among the first to advocate a high tensile 
steel. The method of riveting this material was also the 
subject of careful experiments. 

Research work also resulted in the development of the 
Yarrow water-tube boiler, now so extensively adopted for 
all types of warships. The horse-power of Yarrow boilers 
constructed by the firm up to this date exceeds 800,000, 
and the output of their licencees in this country and 
abroad is about double this total. 

In connection with high-speed propelling engines for 
torpedo craft, with petrol engines for motor l>oat>. etc., 
and later with turbine machinery, the firm have done 
original work, particularly in connection with the reduction 
of vibration, the efficiency of screw-propellers, and the 
influence of depth of water upon the speed of ships. 

It will be readily understood that a firm which attacks 
h"om a scientific standpoint all such mechanical problems 
will attach great importance not only to the suitability of its 
manufacturing plant, hut also to the deafen of its workshop- 







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THE WORKS AT POPLAR 



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Some years ago they entirely 
reconstructed their works at 
Poplar.' and Sir William Arrol 
and Company, Limited, designed 
and built for them at that 
time a boiler shop, platers', and 
machine shop, having a length 
of :YM) ft, and of a breadth and 

height shown on the annexed 
section. These works are illus- 
trated on pages 179 and 181. 

In the course of time, however, 
owin- t<> the great expense of 
construction, due to the exces- 
sive rates and to the high cost 
of labour in the East end of 
London. Messrs. Yarrow were 
forced to remove to a district 
offering more economical con- 
ditions, and a site on the north 
bank of the Clvde. three or 
four miles west of Glasgow, was 
chosen. There, at Scotstoun, 
entirely new works have born 
built." and as a consequence of 
experience of Sir William Arrol 
and Company's work, the con- 
struction of all the shops was 
entrusted to them without even 
a formal contract. 

1 Sec Engineering, vol. Ixxi., page HI. 

3 See Engineering, vol. [xxxi., page 353; 
vol. Ixxxiii., page 571. 























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182 



narrow's new works at Glasgow 



The total area of the new works is 12£ acres, but 
the Company have purchased for extension an equal 
area of vacant land immediately to the east of the new 
site. On the area occupied, which has a frontage to 
the river of 750 ft, with a depth of 700 ft., there is 
being constructed a fitting- out l>asin 320 ft. long and 
85 ft wide, set at a slight angle to the flow of the 
river, so as to facilitate the entrance and exit of vessels. 
To the east of this there are eight building berths, 
at the head of which the platers" shed has been con- 
structed. The carpenters' and pattern-makers' shop and 
the smith v are to the west of the basin. 

On the landward boundary, on the west side of the 
entrance, there is the machine shop, illustrated on the 
opposite page. The total length is 248 ft., and there are 
three bays, of a total width of 155 ft. 6 in. To the east 
of the entrance there is a boiler shop of 303 ft. in length, 
with three bays of a total width of 153 ft. The offices 
are located between these two shops, with the entrance, 
close by which the railwav siding passes. 

One of the new features is the construction of a 
yard gantry, 330 ft. long, with a height above the ground 
level of 26 ft, for the accommodation of a 7-ton electric 
crane of 85-ft. span. The space below this gantry is to be 
used for building shallow -draught steamers for shipment 
in pieces. 

The fitting-out or tidal basin is completely covered 
over by a rooting, entirely glazed, carried on columns 
92 ft. apart transversely, and 55 ft. longitudinally. The 
whole area of this basin is commanded by a 50-ton electric 

crane. 

The total width of the building over the tidal basin is 
140 ft., consisting uf the main gantry building and two 


















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HARROW'S NEW WORKS A I GLASGOW 



lean-to roofs at the sides. The workmen engaged on the 
wharf or aboard the vessels, will thus he protected from 
weather. 

Tiie whole of the work wdl thus be carried on under 
roof, except that done on the building berths. 



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Parsons Marine Steam Turbine Company, 

Ltd., Walisend on=Tyne. 

rilHK buildings within which so many of Parsons marine 
*■ steam turbines have had their origin were constructed 
by Sir William Arrol and Company. Limited. This new 
prime mover has become, in a comparatively few years, one 
of the most largely adopted engines for high-speed ships. 

As indicating the progress of the turbine, it may he 
stated that whereas in the beginning of 11)00 there was 
only one vessel driven by this engine, the power of marine 
turbines in use increased to 70,000 shaft horse-power at 
the end of 1903, to 150.000 horse -power in 1904, to 
270.0(H) horse-power in L905, and to 390.000 horse-power 
at the end of L906. The total horse-power of Parsons 
marine turbines completed and on order is now 1,250,000, 
including the machinery behm built bv the licensees and 
by the Parsons Company. 1 

The Company constructed new works at Wallsend-on- 
Tyne in 1899, where the principal machine shops were 
erected by Sir William Arrol and Company, Limited, 
including, as noted in Table II., page 144. erecting shops, 
pattern shops, foundries, smithies, test-houses, etc." 

On the opposite page there is reproduced an engraving 
of the erecting shop, which is 385 ft long and 80 ft. broad, 
with a height of 44 ft. 

1 See "Marine Steam Turbine Development," by Hun. C. A. Parsons and K, •'• 
Walker, in the Proceedings of the North-East Coast Institution of Engineers and Ship- 
builders, March, 1907. 



See Engineering, vol. lxviii., pages 191, 221, 255. 



"mpam. 



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Babcock and Wilcox, Ltd., Renfrew. 



/\I'I( next illustration shows the machine shop of 
^' .Messrs. Babcock and Wilcox, Ltd., the constructors 
of a type of water-tube boiler now very largely adopted 
in the Navy and merchant service. The advance iii 
favour of this boiler is indicated by the following Table, 
showing the horse-power of the boilers manufactured at 
the Company's Works at Renfrew and elsewhere, and by 



v/un. i in inn uinir i JH.^11.^ 


^ "I I I H. V_yi 


Mil 1 let II \ . 






Number of Ships, 

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Number of Boilers. 
1 


radicated Eoi 




power. 


Up to end of 1889 


275 


1890 to 1892 


3 


3 


950 


L893to 1895 

• • • • - • ... 


6 


10 


6,150 


L896 to 1898 


41 


84 


56,345 


189") In nioi 

• ' • • a 


75 


302 


283,925 


\-"^ to 1904 


78 


528 


564,631 


Total to March, L907 


266 


1,268 


1,293,715 



At the Renfrew Works various shops have been con- 
structed, the latest being the marine shop illustrated on 

the opposite page. It is 350 ft long, with a width of 
216 ft. 




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David Rowan and Sons, Glasgow, 

"1TESSKS. D. ROWAN AND SONS have occupied a 
■^^ favourable position amongst the Clyde engineers 
almost since the beginning of the steam era. In recent 
years, under the superintendence of the late Mr. James 
Rowan, the son of the founder, and <A' his partner. Mr. 
William Thomson, the works Mere entirely reorganised, 1 to 
make the most of the available area, which is especially 
valuable, as the establishment is located in a fairly 

* 

crowded part of Glasgow. At the same time an admir- 
able system of management was instituted. It was in 
connection with this rearrangement that the firm modified 
the premium system of wages, which has been widely 
applied. This system was described in papers read at the 
Engineering Congress held in Glasgow in 1901. J But here 
we are concerned only with the machine shops. 

The boiler department is 234 ft, long, the erecting 
shop being of 90 ft. span, and the light plating shop of 
60 ft. span. The roof, it will be seen, is light in structure, 
and affords abundant natural lighting- 

The 90-ft. span is served by three travellers, which 
extend the full width, and have a capacity two of 
4<> tons and the other of 2.5 tons. The work done is for 
"'••reliant steamers, and experience has shown that the 
great majority of the loads for the heavy crane consist 



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See Engineering, vol. Ixxiii., page 597. 

-•• Engineering, vol Ixxii., pages 351, 379, 383 




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BOILER WORKS 



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of the shells of single - ended marine boilers weighing 
from is to 20 tons. In the light plating department the 
overhead cranes are of 10 to 20 tons capacity. 

The view on the preceding page illustrates the boiler- 
erecting department looking north : while on the opposite 
page there is a view of the east bay, where light plating 

work is done. 

In addition, two engine shops were constructed, the 
larger and later of 220 ft. in length and 57 ft. span, with 
a heiffht of 57 ft. Details of the various buildings by 
the Coinmnv for this firm are given on the TaUe on 

page 143. 



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G. and J. Weir, Ltd., Cathcart 

"TT^EIR'S pumps. Weir's feed-heaters, and one or two 

** other auxiliaries for marine and land machinery 
enjoy a universal reputation, not only because of the 
excellence of design, but because absolute reliability is 
ensured as a result of specialised manufacture. This is a 
consequence of progressive management, and the works of 
the firm at Cathcart 1 are not only well planned and well 
equipped but especially well lighted. 

The principal machine shops have been constructed 
by Sir William Arrol and Company. Limited, and on the 
opposite page are two illustrations, the one showing the 
fitting shop and the other the foundry. The first-named 
is a building 372 ft. long and 41 ft. wide, with a height 
ot 43 ft., and along it there travels an overhead crane of 
30 tons capacity. 

The foundry is 210 ft. long, with a width of 105 ft. 
«nid a height of 44 ft. The photograph reproduced is 
remarkable as illustrating the effect of the extensive 
glazing of the roof. There can be no doubt that with 
good lighting the work is more expeditiously and more 
accurately carried out. 

1 See Engineering, vol. Lxxi., page 795. 






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Stewarts and Lloyds, Ltd. 

''PHIS firm is probably the best-known iron and steel 

tube manufacturing concern in the world, representing, 

as it does, the amalgamation of the two largest produced 

in this country. The illustration on the opposite pa-,' 

shows the several Lays of an extensive s wind, was 

designed and built by Sir William Am.l and Company 
Limited, in 1906. 

This building, whirl, i 8 600 ft. long and of a total 

width of 480 ft, has a height of 36 ft. It is part of the 

mpenal Works at Coatbridge, X.B.. and the view shows 

that notwithstanding the smoke which is usually associated 

with the work of tube making, a light a dear atmosphere 

is possil.l,. „•!,«, some effort is made to achieve it 



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Neilson, Reid, and Co., Ltd., Glasgow. 

(Now North British Locomotive Company, Ltd.) 

rilHIS firm, which has recently been formed with others 
-^ into the North British Locomotive Company, Ltd.. is 
one with a splendid historical record, having constructed 
locomotives, not only for many of the British lines, but for 
nearly every country in the world. It has thus assisted 
materially towards the maintenance of British prestige in 
this department of mechanical engineering. 

During the last decade of the nineteenth century very 
extensive reconstruction works were carried out at the 
firm's works at Springburn, Glasgow, and several new 
shops were built by Sir William Arrol and Company, 
Limited. 

A representative erecting shop is illustrated on the 
opposite pa^e. The length is 706 ft,, the width 44 ft., and 
the height 54 ft. It is traversed by three cranes, one of 
which has a capacity of 75 tons. The view offers a 
suggestion of the extensive character of the work carried 
out by the firm, owing to the presence of so many loco- 
motives, that in the foreground being one of several 
compound engines constructed for the Dutch railways. 

Still later, new works have been constructed at Pol- 
madie for the North British Locomotive Company, Ltd. 
These cover an area of about two acres, and the dimensions 
of the buildings are given on the Table on page 144. 














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144 




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( 200 ) 




John Spencer and Sons, Ltd., Newburn. 






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ODE next engraving is a view of one of the latest 
machine shop- built for the Newburn steel Works 
of Messrs. John Spencer and Sons. Ltd., an establishment 
founded in L810 by John Spencer. He was a maker of 
tiles in works at Newcastle, and these were carried to 
market on the hacks of donkeys. 

Later. Mr. Spencer concluded that it would be profit- 
able to make his own steel, and a converting furnace vyas 
accordingly laid down at Newburn, to which site he had 
been attracted by the available water-power, which was 
used for driving the train of rolls for forming tin* steel 
In 1845 a steam engine was purchased, and was the first 
engine used for driving a train of rolls directly. Spring- 
making and other units for railway stock were early 
products of the firm, which has developed until it now 
occupies a prominent place among the producers of steel 
forgings for heavy marine ami other machinery. 1 

The fitting shop, erected by Sir William Arrol and 
Company, Limited, illustrated on the opposite page, has a 
length of 335 ft. and a width of 77 ft., with a height of 
51 ft. The electric cranes fitted range up to 50 tons 
luting capacity. • 

1 S. Engineering, vol. Ixxiw. i a 134. 





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( 202 ) 



Marshall, Sons, and Co., Ltd., 

Gainsborough. 



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A S representing another class of engineering factory, 
-^- we reproduce on the facing page an engraving of 
a new boiler shop built by the Company for .Marshall. 
Sons, and Co., Ltd., of Gainsborough. This establishment 
lias long been identified with general engineering and 
millwright work, while the manufacture of boilers of all 
types has for many years been one of the prominent 
successes of the firm. 

The works were originally founded in 1848, when a 
small engineering and general millwright's business in 
Gainsborough was purchased bv Mr. William Marshall. 
Operations were at first conducted on a very small scale, 

but eventually I 1 , acres of land were purchased, and on 

this the nucleus of the present works was founded in 
1855-56. 

The business has since grown to enormous proportions, 
and over 120,000 engines, boilers, etc., have been turned 

out of the Britannia Works. 

The new boiler shop, which is illustrated on the 
opposite page, has a length of 400 ft. and a width in 
three hays of 175 ft., the height being 56 ft. There are 
eleven overhead cranes, ranging from 30 tons to 5 tons. 



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The Charing Cross, City, and West End 
Electric Company, Bow Station. 

I )Y way of variety, our next illustration is a view of 
an electric-power station for this well-known Metro- 
politan Company. Sir William Arrol and Company. 
Limited, designed and built a boiler house 300 ft. long, 
with a width of 77 ft. and a height of 93 ft., and an 
engine house. 300 ft. long, with a width of 76 ft. and a 
height of 93 ft, the latter having an overhead crane of 
30 tons capacity. This was for the Bow Station of the 
Company. 1 

1 See ExGiXEEruN-G. vol. Ixxxi., pages 63 ami 96. 



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A. Guinness, Son and Co., Ltd., 

Dublin. 



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rilHE two engravings on the opposite page illustrate 
-*- stages in the process of riveting a steel building 
for this famous firm of Dublin brewers. The building is 
165 ft. by 146 ft. and the total height is 116 ft. As will 
be seen, it is constructed of built-up square standi ions. 
with plate girders and joists, the outer covering being of 
masonry. The work was done very expeditiously, the 
time occupied being twenty months from the date of 
signing the contract. 



Ltd.. 







Storage Building at Guinness's Brewery in Course of Construction. 

ist January, 1904. 










Storage Building at (iuinness's Brewery in Course of Constructiou 

3rd May, 1904. 





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Chimney Stack. 



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trated on this pa^e, in the form of a steel chimney 



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stack, constructed at Guinness'a Brewery in Dublin. It 
•ias a total height of 172 ft. from ground level. 




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MECHANICAL ENGINEERING. 




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Experience and its Application. 

rilHE success of the large bridge and other constructional 
X works undertaken by Sir William Ariol and Company, 
Limited, is due not alone to design, but in part to ingenuity 
in devising suitable engineering appliances and to fore- 
sight in providing against difficulties in manufacture and 
erection. The varied necessities of each case involve almost 
continuous research and invention, and a consequence is 
the production of efficient machinery of all kinds. 

The beginning of the now extensive engineering 
section of Sir William Arrol and Company's Works dates 
practically from the evolution of the hydraulic riveter, when 
Sir William Arrol was compelled to enter upon the experi- 
ments which brought success by the workmen going on 
strike during the building of one of the early bridges of 
large dimensions. This use of hydraulic power led to a 
closer study of pumps, and many installations have been 
manufactured. The making of presses, cranes, and special 
machine tools followed, and air compressors, air locks, and 
other appliances for bridge pier and shaft sinking were 
soon added. 

Experience in the use of such appliances is, in all 
cases, carefully collated ; and thus from time to time 
improvements have been effected, so that the mechanical 
engineering productions of the Company have attained a 

high degree of efficiency. 

In the succeeding pages there are illustrated some of 
these productions ; many of them are in use in the 
principal works in the country. 












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Hydraulic Pumps. 

FIRST reference may be made to hydraulic pumps, in 
connection with which the Company have had very 
considerable experience. The illustration on the opposite 
page shows a typical set supplied for the Ordnance Works 
at Barrow-in-Furness of Messrs. Vickers Sons and Maxim, 

Limited. 

The water is compressed to L500 11). per square inch, in 
tour hydraulic cylinders having rams 2% in. in diameter. 
These cylinders are arranged in pairs, placed back to back; 
each pair is operated by one steam cylinder, and compression 
takes place in the water cylinders alternately. This secures 
a more equal turning moment, and minimises the stress 
on the working parts. The rams are worked direct from 
the piston of the steam cylinder, the ram of the rear 
water cylinder being connected to the steam - piston 
crosshead through top and bottom rods extending to the 
pump-rod crosshead, as shown in the engraving. 

The steam engine is of the compound type, the 
diameter of the high-pressure cylinder being 10 in., .and 
of the low -pressure cylinder 27 
24 in. 

An extension of the piston rod through the cylinder 
end actuates, by disc-cranks, a shaft on which there is a 
fly-wheel. The normal speed is (JO revolutions per minute, 
which is equal to a ram speed of 240 ft. per minute. 

Pumps of this type are to be found in a large 
number of the industrial establishments throughout the 



in., with a stroke of 







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214 



ELECTRICALLY-DRIVEN PUMPS. 












kingdom. Sir William Arrol and Company, Limited, also 



make pumps of 
electricity. 

w 

The view on 
of pumps driven 



corresponding power fco he driven by 



the 

by 



and. as indicative of 



opposite pai>e illustrates such a set 
a direct-coupled slow-speed motor; 

the jjeneral character of hydraulic 
pump work, we may here give a quotation from a 
standard specification. 

"The gear-wheels an- machine-cut, t lie pinion is in mild steel, and Che wheel in 
tough cast ip'ii Tin- crank-shaft is a steel forging "1 ample proportions, and the 
crank-pins are turned out of the solid forging. There are three single-acting pump 
rams working oil" the crank-shaft, and pumping iut<> a enimnon deliver} i 1 '!"'- The 

connecting-rods and crossheads axe in cast steel, and the wearing surfaces i 

liberal proportions. The pump castings are in mild casl steel, and the sole-plate 
is iii good close-grained cast-iron, and is strengthened by longitudinal and transverse 
ribs. The pumps are bolted to the sole-plate, and rest in truly-bored eatings, 
with recess-checks foi taking the thrust. The glands are verj accessible. The 
pump rams, glands, valves, valve-seats, crank-shafl bushes and connecting-rod lini 
are all in best gun-metal. The valves are of large diameter, and work with a \<\\ 
small lift, so that the wear and tear of the valves is reduced to a minimum. The 
lmitnr lias three bearings, and sits on an independent sole-plate, which is bolted to the 
pump sole-plate by fitted bolts. 

"The motor will run continuously, and the accumulator controls the pumps in 
the following manuei When the accumulator has risen to within 1 ft of the top 
of its stroke, a projecting plate engages with a ferrule on a vertical rod alongside the 
guides, [f the accumulator continues to rise, the rod is drawn upwards, and cl 
a valve, to the spindle of which it is connected. By means of a small hydraulic 
ram at the pumps a porl in the bridge pipe is uncovered, and the watei pumped 
passed hark to the supply tank, and the motor relieved of the greatei portion oi 
its load. The pressure water in the accumulator is meanwhile held up by a check 
valve at the pumps. When the accumulate] falls to half its stroke, the projecting 
plate engages with a second ferrule on the red, and the valve is drawn to pressuie 
again. The small hydraulic ram at the same time closes the relief port. Pumpi 
ls resumed > i11 " 1 the motor again takes the whole load. A light flywheel is providi 
on the motor shaft to assist the motor when the load is taken off and on. The mo! 

IS coutrolle d by a simple starting switch, and the current consumed when rui 
without load i- small.' 1 



If the service required of the 
a controlling switch is arranged 
the action of the accumulator, ii 
that described. 



pumps is intermittent. 

which is worked by 

a similar mannei' to 









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Hydraulic Cranes. 

IX bridge and constructional steel work generally, it 
I frequently occurs thai difficulties are involved in the 
arrangement of manufacturing and erecting plant, because 
of limitations in the space available, and few firms have 
had to face more of such problems than sir William Arrol 

and Company, Limited. 

This resulted in the development of an important 
department at the Dalmarnocfc Works at Glasgow, for 
the manufacture of cranes to meet almost every con- 
tingency. Now few shipyards are without some oi Sir 
William Arrol and Company's hand, hydraulic, or electric 
jib-cranes for feeding machine tools and for other pur- 
poses, and several of these are illustrated and described 
on the five succeeding pages. 

The first illustration shows an hydraulic jib-crane, 
with racking and slewing motion. It is made in various 
sizes up to 30-ft. radius. The jib is at a fixed height, 
and the hook block rises and falls through a height of 
12 ft. to 20 ft. The lifting power ranges from 5 to -20 tons. 

The second illustration shows a type of crane largely 
used for supporting hydraulic riveters and other work. 
The crane occupies little floor space, and has also the 
advantages of facility, speed of movement, and cheapness. 
This type is manufactured of various radii from 20 ft. to 
40 ft., with an hydraulic ram capable of lifting a maxi- 
mum load of .3 tons through from 5 ft. to 12 ft. 



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HYDRA! LIC CRANES. 






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On this and tin* opposite pages there are views of 
two types of crane, both at the Naval Construction 
Works at Dalmuir of Messrs. William Beardmore and 
Co., Ltd. These illustrate modifications of standard types 
to suit special requirements. The crane shown below is 
in the forge; the other is in the boiler shop. The design 
of each is clearly indicated. The speed of lifting of these 




Forge Crane. 



cranes is kept low, varying from 5 ft. to 10 ft. per minute. 
.•is the range is slight and the work must be kept under 



control. 



Several types of crane have been designed for dealing 
with plates and angles in shipbuilding and bridge buildiDg 
yards. A typical crane, illustrated on page -2-2H is one 
which lifts a load of 3 tons at a radius of 40 ft. At 20 ft. 
radius the crane is self-balancing. The foundations for the 
mast are at 7 ft. below the ground level, and there the 
toad is taken on hard steel and gun-metal washers, with 



"■ 




220 



HYDRAULU CRANES 



efficient lubrication. Tlie central bearing is at the ground 
level, and consists of a roller path of large diameter, the 
external circumference of which forms the slewing drum. 
The slewing cylinder is fixed to the side of the mast, and 
the lifting cylinder is within the girders forming the mast 
The jib is built up of channels and angle-ties securely 
braced toother. The crane is built t<» swing through a 



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A Typical Shipyard Crane at Messrs. John Brown and Company's Clydebank 

Works. 

complete circle which is a great advantage. A crane of 
this type is illustrated on the view on this page. 

The first of the illustrations on the opposite page 
shows a 3-ton self-contained hydraulic crane, standing upon 
its own pedestal, as constructed for Messrs. Barclay, Curie 

and Co.'s shipyard. These cranes are very useful in ship- 
building yards for handling plates and angles at the racks. 
They are made of moderate capacity, up to 5 ton and 

30 ft. radius. 



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3 = Ton Pedestal Crane at Messrs. Barclay, Curie and Company's Shipyard. 



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Crane at Vickers Works at Barrow- in=Furness 









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222 



HYDRAULIC CRANES. 



Another form of self-supporting crane is shown in 
the second illustration pn the preceding page. In this 
case the mast swivels round a central forged-steel pin, 
which is shrunk into a cast-iron base-plate. The load can 
thus be brought much nearer the mast than with a 
pedestal crane. The hydraulic mechanism is placed in the 
rear of the mast, and assists in balancing the crane. 



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Hydraulic Riveting Machines. 



i 8 we have already indicated, Sir William Arrol was 
■*-*- the first to apply hydraulic riveting to bridge struc- 
tures, and the system he then evolved w as at once applied 
in connection with the building of large ships and construc- 
tional work generally. From time to time experience 
has enabled improvements to be effected and new forms 
to be evolved to meet unusual conditions. Thus, tools 
are now manufactured to suit all possible requirements. 

Silence in working, freedom from vibration, and the 
minimum of wear and tear are among the advantages 
claimed for these machines. The pressure exerted on the 
rivet is gradual, and can be maintained until the rivet 
is cold, which, in the case of thick plates, is important. 
In girder work about 200 rivets per hour can be closed 

with this make of riveter. 

On the six succeeding pages there are illustrated and 
described several types of portable riveters, used largely 
in connection with the riveting of heavy girders, of the 
double-bottom structure of large steamships, and of a 
great variety of other structures. 

"Scissors" riveters (as illustrated on the next page) are 
made up to 75 in. gap. The hobby arms are cast in Siemens 
steel, and truly machined on large side-bearing surfaces 
at the hinge; "the hinge pin is of the best forged steel, 
and the dies are of hard cast steel. The cylinder 
cover is of mild steel, the piston of gun metal, and the 







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HYDRAULIC RIVETING MACHINES. 



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rkinff valve, of* the piston type, is of gun metal. A 
relief arrangement is provided, so that, in the event of tl. 
anus being 1 closed when the dies are not in place, no 
damage is done in the cylinder head, the water escaping 
Two hangers are provided, so that the dies may be worked 
in a horizontal or vertical position : by moving the point 



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The "Scissors" Type of Hydraulic Riveter. 



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of the suspension to the right or left along the hanger 
the dies will lie at a corresponding angle. The machine is 
specially suitable for riveting in corners or confined spaces 
The "how" riveter-, of which a type is illustrated on 
the opposite page, range from -24 in. to 69 in. gap. The 
main casting is in Siemens Martin steel : the piston is a 
steel forging, and the cylinder is lined with ffun metal. 

The operating valve is of the piston type, and is in gun 

metal. 



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HYDRAULIC RIVETING MACHINES 



'2-25 



The machine illustrated <», thi* ,.« • i 
toa ^ hanger but i , . ' "* M R,,owu ^l"'"-le,l 

ot the outer flange, and is bored with 



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The "Bow" Type of Hydraulic Riveter, 

bolt holes, closely pitched, so that the machine can be 
slung with the riveting dies either in a horizontal or in 
-'' vertical position. 

By the engraving on the next page there is illustrated 
<i machine for riveting light steel-plate pipes from about 
;) n »- in diameter upwards. For this work the cylinder 




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226 



HYDRAULIC RIVETING MACHINES. 



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is, as a rule, proportioned to give a pressure of 5 tons 
on |-in. rivets. The cylinder is lined with gun metal, and 




Machine for Riveting Light Steel Pipes. 

is tunned in the frame of the machine, which is a steel 
casting. The holder-up, as shown in the engraving, is 
circular in form. The use of high-tensile steel minimises 
its recoil. The holder fits tightly into a socket in the 
main castings. The machine is mounted on a cast-iron 
stand, and has proved very convenient in connection with 
the making f the light steel pipes now so greatly in 
demand for water and other supply-mains. 

The "hinged" type of riveter, which forms the subject 
of the next engraving, has a patented parallel motion. 
by means of which the pressure is exerted in the 
line of the rivet, so that any danger of twisting the 
rivet head is obviated. This riveter is verv largely used, 



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HYDRAULIC RIVETING MACHINES. 

as it is light and handy, and suitable for 
of work. 



•1-17 



a great variety 




"Hinged" Type of Hydraulic Riveter. 

The engraving on page u 229 illustrates the application 
of hydraulic riveters. The view shows the double-bottom, 
up to the margin plate, of one of the recently built 
turbine -driven Cuiiard liners. 1 Many of the plates were 
H in. thick, 32 ft. long, and 5\ ft. in width. In many 
cases the plates were quadruple riveted; the sheer strake 
was quintuple riveted, J \-\\\. rivets being used. 

The riveting done by hydraulic power included the 
centre girder keel-plate, garboard strake. the centre of the 
inner bottom, the intercostal girders, the end frames to 
the reverse angles of the beam-knee brackets, the bridge 



See E.NiiixiiBRi 



MG, voL Ixxx., page 716; vol Ixxxi., page 729. 






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228 



HYDRAULIC RlV£TERS ON CUNARD LINERS 



D 



deck sheer strake, the shelter deck stringer angles, and 
the side stringers between the web frames. 

The rivets in the shell and tank top plating vary from 
2 in. to 11 in. in diameter, spaced on an average four to 

r 

five diameters apart. In the bulkheads the rivets are 

generally | in. in diameter, spaced four to five diameters 

apart : the deck rivets are f in., spaced four to five 
diameters apart. 

The riveting machine was carried on a beam which 
had on the opposite end a counterbalancing weight. This 
beam was supported in the centre upon a lattice -work 
column running on wheels, or on a small truck on the 
railway track laid on each successive deck as soon as 
there were beams to carry it. 



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Hydraulic Retort=Machinery for Gas 



Works. 1 



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ESEARCH work in general hydraulic mechanism 
^ led Sir William Arrol, early in the 'nineties, to 
associate himself* with the late Mr. William Foulis, the 
as engineer to the Corporation of Glasgow, in experiments 
which resulted in the evolution of hydraulic machinery 
for undertaking- the most laborious work in connection 
with the production of coal gas. 

This plant now includes a machine for charging the 
retorts, another for withdrawing the coke, and a third 
for cleaning the ascension pipes. The labour cost is 
greatly decreased, the time occupied in the various 
operations has been minimised, and the output of gas 
from a given number of retorts has been increased. 

The first commercial application of the system was 
in 1894. Since then, nearly all the large towns in Great 
Britain, and many abroad, have adopted the plant. There 
are installations at Vienna, Amsterdam, Berlin, and Cleve- 
land in the State of Ohio. In London the Gas-Light 
and Coke Company, the South Metropolitan Gas Company, 
the Commercial Gas Company, and others use the system 
extensively. It is also applied at works in Bromley and 

' See Pwfessoi Jamieson'fi "Applied Mechanics," vol. ii., page 324 (Griffi] 
Proceedings of Institution of Mechanical Engineers, 1895, Parts III. and IV, pag 1; 
ENGINEER^©, vol. lx., pages 153, 312; vol. Ixxxi., page LIS. 






THB TRAVERSING MECHANISM. 



231 



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Southend. In the provinces it is only necessary to 
mention Birmingham, Glasgow, Liverpool, Leeds, Hull, 
Bolton, Brighton and Dundee, to indicate the wide extent 
of the utilisation of the system. 

There are certain variations in the mechanism to meet 
different conditions, but the general principle is the same ; 
and it is, perhaps, only necessary to describe one installa- 
tion in detail. 

The carriage for all three machines is of the same 
general construction, and the same method of traversing 
is adopted in all cases. The frame is a simple rectangular 
structure of plates and angles, carried on axle brackets of 
cast steel, and of dimensions to suit the height and width 
of the retort-charging platform. The machine is traversed 
along the front of the battery of retorts by an hydraulic 
motor, which works through bevel gearing direct on to the 
axle. 

The size and power of the motor varies with the 
different machines. Thus, the charging machine, which 
has ;\ weight of about 13 tons, including 5 tons of coal in 
the hopper, is traversed by a 4-horse-power motor at a 
speed of 70 ft. per minute ; the drawing machine, of about 
4 tons, is traversed by a li-horse-power motor, at a speed 
of 150 ft, per minute; and the ascension pipe - cleaning 
machine, of 6 tons, has a 1^ brake horse-power motor of 
the capstan type, and is traversed at a speed of 100 ft. 
per minute. 

In the frame thus traversed there is carried a beam 
built up of steel channels, to support the gear for 
charging, for withdrawing, or for cleaning the pipes. In 
order that the level of this platform may be varied to 
suit the height of the mouthpiece of the retort, there is 
hydraulic mechanism for raising and lowering it, as clearly 



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232 



RETORT-CHARGING MACHINE. 



shown in some of the views. The steel channels of this 
horizontal beam or platform work in vertical angle guides 
on the main framing, and the whole is suspended on two 
lifting chains, one at the front and the other at the rear. 
These chains pass over guide pulleys carried on the top 
of the framing, and thence over separate pulleys secured 
to the ram-head of the hydraulic mechanism. The position 
of this elevating cylinder varies in different machines. In 

some cases it is on the top of the frame, working 

horizontally ; in other instances it is placed vertically on 

the side of the frame, but the action is the same. 

Directing attention now to the mechanism for charging 
retorts, a word may first be said regarding the supplv of 
coal. This varies with the general arrangement of the 
retort-house. 

At the Beckton Works of the Gas Light and Coke 
Company, Ltd., as illustrated on the opposite page, the 
coal wagons are discharged into coal stores under the 
track at the side of the retort-house, whence the fuel is 
conveyed by elevators to hoppers built over the retorts. 
The coal is Uh\ from these through shoots to a hopper on 
the charging machine, as shown clearly on the engraving 
opposite. For regulating the supply there is fitted to the 
shoot a valve, which is manipulated from the retort floor. 
The total height of the Beckton retortdiouse from ground 
level is 55 ft., and the width 70 ft. In the various 
retort - houses there are sixteen charging and sixteen 
drawing machines, 

machines. 



with several ascension pipe-cleaning 



The eoa] .Imps fro m the hopper on to the charging 
pan through a regulating chum, built of a series of plat 
radiating from the centre. This drum, ntted at the base 
of the hopper, is rotated by an hydraulic cylinder. It is 



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Retort-Charging Machine at the Beckton Works of the lias Light and Coke 

Company, Limited. 

of the retort : and as it falls on to this pan it is pushed 
into the retort by a shovel actuated in successive strokes 
by an hydraulic ram on the horizontal beam. 



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EFFICIENCY OF RETORT-CHARGING MACHINE. 



This hydraulic ram, like all others in the system, 
works at from 400 II). to 700 11). pressure, which experi- 
ence has shown to be the most suitable, as it minimises 
the diameter of the cylinders and flexible piping. The 
latter is of india-rubber and canvas, bound with wire, and 
tested to L500 lb. per square inch. 

The coal is. at the first stroke of the ram, pushed 
to a point about 12 in. from the back of the retort — or 
from the centre in the case of a double-ended retort — and 
successive charges are then deposited about 18 in. apart; 
the depth of coal in the retort being regulated at about 
8 in. The distance apart of successive charges is fixed 
by a bar on the beam which actuate stopper - plates 
to engage with the charging ram at each successive 
stroke. Thus, when the machine has once been set, the 
whole operation is automatic. 

The machine is completely controlled in all its 
connections from one platform, the handles for operating 
all the valves being centralised there, and a retort. 
20 ft. long, can be charged from both sides, as at the 
Beckton Works, in from 15 to 20 seconds. The average 
time occupied, including the work of traversing the 
machine from retort to retort, and setting it to suit 
the height, is about 45 seconds, and as many as forty- 
eight retorts have been charged per 
sufficient time each hour to give the 
the machines a rest. 

Where the coal is of a quality to give off its gas 
m three hours, one machine would suffice for 120 retorts; 
but where the coal requires six hours for generating gas, 
ea^h machine could deal with 240 retorts. 

There are several alternative arrangements for dealing 
with the coal. An elevator is sometimes fitted to the 



hour, allowing 
men operating 












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ALTERNATIVE SYSTEM OF RETORT-CHARGING MACHINE. 

machine for picking up coal from the side bin, and dis- 
charging it into the hopper at the top. This machine, which 
is illustrated on this page, is very useful in retort-houses 




Charging Machine at the Vauxhall Works of the South Metropolitan Gas 

Company, Limited. 

with side coal-stores. The machine illustrated is in use 
at theVauxhall Ons Works of the South Metropolitan Gas 
Company, Ltd, The elevator buckets work freely in the 



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236 



RETORT-DRAWING MACHINE. 



projecting skirt of coal, and are drawn hack out of the 
coal when the machine is travelling. For this purpose, 
an hydraulic cylinder is fitted to the bottom end of the 
elevator frame. The top end of this is pivoted, while the 
bottom end is mounted on side rollers running in guides 
at the side of the machine. These guides have a slight 
upward gradient, so that the bottom of the conveyor is 
raised clear of the coal on the floor. All the other 
motions are as on the ordinary machine, and the operator 
controls all motions, including the manipulating of the 

elevator. 

The drawing machine is simpler in construction. As 

in the case of the charging machine, there is a horizontal 

beam carrying two hydraulic cylinders, one for driving 

a rake forward into the retort, and the other for drawing 

it out. The lever which actuates the valve for working 

the rake is so attached to the beam that the movement 

which sets the hydraulic valve for the forward move- 
incut of the rake simultaneously depresses the hack end 
of the beam, raising the rake to allow it to pass over the 
coke in the retort. The reverse movement of the lever, 
while actuating the valve of the cylinder for withdrawing 

* 

the rake, elevates the hack end of the beam, whereby the 
end of the rake is lowered into the coke. 

The rake does not withdraw the full contents of the 
retort at one stroke. At each successive stroke it enters 
the retort for a greater distance, the length of the travel 
being regulated at the discretion of the operator by the 
extent of the opening of the hydraulic valve. The return 
stroke of the rake is checked by an india-rubber buffer. 
placed at the end of the horizontal beam; but a little 
experience enables the operator to regulate the motion by 

the working of the valve. 



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RETORT-DRAWING MACHINE. 



237 



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The greater part of the exhaust water is returned to 
a «ast-iron box, placed above the beam, whence it is 
allowed to flow continually over the rake-head and rod 
to cool them. 

Various forms of rake-heads have been tried. The 
form now applied consists of a east-iron head pivoted to 
the lake to enable it to swing slightly. 




Machine for Withdrawing Coke from Retorts. 

This machine takes about thirty seconds to draw a 

charge from the retort. 

The latest development is in the construction of a 
machine on the same lines for cleaning the ascension-pipes 
of retorts. Many attempts have been made in the .past 
to construct such a machine, but none succeeded until Mr. 
Andrew S. lii-art, of Sir William Arrol and Company, 
Limited, in collaboration with Mr. G. C. Trewby, the Late 



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238 



MACHINE FOR CLEANING ASCENSION PIPES OF RETORTS. 









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chief engineer of the Gas Light and Coke Company, Ltd., 
evolved a method whereby a flexible shaft with an auger 
point, is forced up the ascension-pipe by hydraulic power, 
while being rotated at a speed to suit the density of the 

deposit on the pipe. 

This machine was first tried at the Beckton Works 

of the Gas Light and Coke 
Company in 1905. 1 There 
were some difficulties inci- 
dental to the first application, 

I mt from the outset it was 
evident that the inventors 
had worked on the right 
lines ; and now, as the re- 
sult of experience, various im- 
provements have been made, 
some of them suggested bv 
the engineering staffs of the 
Gas Light and Coke Com- 
pany's Works, and of the 
Vauxliall Works of the South 
Metropolitan Gas Company. 
These improvements have 
been embodied in the later 
machines, of which illustra- 
tions are given in pages 239 
and 241. 

The frame and traversing mechanism are the same as 
in the charging and drawing machine. The beam carrying 
the hydraulic mechanism for cleaning the pipe is simi- 
larly raised and lowered within the frame. At the outer 
end of this beam there is fixed an hydraulic ram 21 in. 

1 See Engineering, vol. baud., page 415. 




Machine for Cleaning Ascension 
Pipes of Retorts. 



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Machine for Cleaning Ascension Pipes of Retorts. 



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MACHINE FOB CLEANING ASCENSION PIPES OF RETORTS. 



in diameter and 2 ft. 2 in. stroke, for racking the cleaning 

shaft inwards and outwards. The change-speed wheels, to 
he referred to later, and the motor for rotating the shaft 
for cleaning the pipe, are supported on brackets, which 
assist to hind the framework together, and give it stiffness. 

The design of the shaft for cleaning the pipe is the 
result of considerable experiment. Toothed ferrules strung 
on a wire rope, witli ball-and-socket joints to take the 
thrust, afforded considerable success; but subsequently it 
was decided to build up the shaft of a number of sections, 
as this construction readily adapted itself to inequalities 
in the pipe. Experience also showed that a variation in 
the speed of the shaft became necessary, as the tarry 
deposit was at times hard and tenacious, at other times 
stiff and glueish, or soft and easily removable. The maxi- 
mum efficiency could not be uot always with a uniform 
speed. It was therefore decided to arrange differential 
speed gear in connection with the rotation of the shaft. 

To admit of lateral motion for the driving of the 
shaft up the pipe, the wheels for rotating the shaft are 
mounted on a sleeve, into which the shaft is keyed by a 
sliding feather. The shaft is driven forward through the 
sleeve and up the ascension pipe by means of a horizontal 
hydraulic cylinder, while the sleeve and shaft are rotated 
by a triple-cylinder hydraulic motor working a counter- 
shaft, on which arc pinions gearing into the spur-wheels 
on the sleeve. 

All the motions are independent of each other, and 
are controlled by separate cocks; the whole of the working 
handles are located together, convenient to the operator 
standing on the end platform. 

The cleaning machine in ordinary work at the Vaux- 
hall Gas Works satisfactorily deals" with fifty-two pipes 



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MACHINE FOK CLEANING ASCENSIOH PIPES OF RETORTS. 



•_'4I 



within an hour, allowing sufficient time for rest for the 
operator upon the completion of each lot of pipes. 

The practice, where charging, withdrawing, and cleaning 
machines are used, is for these machines to follow each 








Machine for Cleaning Ascension Pipes or* Retorts 




other in the order desired. All of the pipes are syste- 
matically cleaned each shift, although this may not be 
necessary in all cases. With these three machines very 
economical results are achieved, even in relatively small 
li.ii teries of retorts. 






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( 242 ) 




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Coal Elevating and Conveying Plant. 

IX connection with the retort-stoking machinery for gas 

works described in the preceding pages, a number of 

auxiliary machines are manufactured by Sir William Arrol 

and Company, Limited. These include' coal breakers, coal 

elevators, coal (. veyors, and wagon tips. 

A wagon tip, coal .'levator, and storage hopper are 
shown in the illustration opposite. The rear end of the 

wagon, it will be som. has been raised by an hydraulic 

ram for the automatic discharge of the coal' into a 

popper underground, from whence it passes down inclined 

Chutes to the hoot of an elevator, wind,, in turn, raises it 

to the hopper on the high level. Where required, con- 
veyors are also provided. 

The elevator is driven by an electric motor of 5 horse- 
power, and can raise 20 tons of coal per hour 

Large installations of coal handling plant have been 

nstalled at various gas works and power stations, and 
deal Ultl ' m *U">n 8 of tons of coal annually 



\ Plant. 



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, 244 I 






Hydraulic Motors. 






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/ \N the opposite page we illustrate three types of 
^ hydraulic motors. The first is that used extensively 
for working conveyors and for slow speed driving generally. 
The cylinders, three in number, are formed along with the 
framing in one casting. The crank -shaft bearings are 
incorporated with the bottom and pedestal castings. The 
cylinders are lined with gun-metal, and the pistons are 
of the same material. 

These motors are made in two sizes; (1) of 6 brake 
horse-power, in which ca.se the cylinders are 4! in. in 
diameter and of 6-in. stroke; and (2) of 20 brake horse- 
power, having three cylinders, 6 in. in diameter and of 
8-in. .stroke. The motors work up to 60 revolutions per 
minute. 

The second illustration shows a traversing motor with 
three cylinders set in one plane, and with all the pistons 
operating a single crank. These cylinders are 2£ in. in 
diameter by 3-in. stroke. The machine has been brought to 
high efficiency, as the result of experience, especially in the 
traversing of gas-retort machinery. Similar machines have 
been used on the traversing carriages of riyeting machines 

in shipbuilding yards where hydraulic power is available. 
Phe special feature is a patent reversing valve, by which 
the machine is reversed by a slight motion of an auxiliary 
shdmg valve. Actuated by hand, it admits or exhausts 
Water to or fr the Ports in the main circulating rotating 



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Traversing Motor. 




Capstan Type of Hydraulic Motor. 




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IIVMK.M'LK' MOTORS, 



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valve — a simple method of starting and reversing the 
machine. 

The third engraving illustrates a three-cylinder motor 
also of the capstan type, the connecting-rods working upon 
one crank-pin. In the illustration given on the preceding 
page, the motor is mounted on the axle of the working 
beam of a machine for cleaning ascension pipes; but it 
is made of many sizes, and is extensively adopted for 
many purposes. The cylinders in the machine illustrated 
are Si in. in diameter by 4-in. stroke, and work with a 
pressure of 600 lb. per square inch at 60 revolutions per 
minute, which gives 4 brake horse-power. 






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Hydraulic Valves and Fittings. 

rilHE success of hydraulic plant is influenced to a large 
-*- extent by the efficiency and durability of the valves, 
fittings and details ; and it is in this direction, as much 
as in any other, that Sir William Arrol and Company, 
Limited, are able to give clients the advantage of the 





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No. I.— Standard Stop Valve. 



No. 2. -Tapered Flat-Faced Valve 



extensive experience gained in working their own hydraulic 
plant. A few typical fittings may therefore be described 
and illustrated, as they are made not only for the firm 8 own 
plant, but separately for other hydraulic installations. 

The section marked No. 1 is a standard hydraulic stop- 
valve, generally used on all hydraulic plant made by the 
firm. The valve spindle is set at an angle of 45 deg. to 
the supply pipe, so that there is the minimum interference 
with the now of water through the open valve. 

The Section No. 2 shows a Hat-faced valve largely 

used on riveters. 



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248 



HYhKAl'LU VALVES AND FITTINGS. 



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A standard hydraulic slide-valve is illustrated by the 
►Section No. 3. The lower portion is in gun-metal, with a 
hard seat sweated and pinned on ; while the top portion 
is in cast iron. For low and medium pressures this type 
is satisfactory. 

The elevation and section No. 4 illustrate a standard 
hydraulic piston-valve, which is made in large numbers 
by the Company. 




No. 3.— Standard Slide Valve. 



Open to 
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frees Inlet 




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No. 4. Standard Piston Valve, 



















It is balanced in all positions, and can therefore be 

actuated with great ease. At the same time there is 

little wear and no necessity for re-grinding. In the event of 
the working leathers requiring to be renewed. the\ can 
be replaced in a few minutes. The smaller valves up to 
1 in. in diameter are made entirely of gun-metal : the 
larger valves have gun-metaJ liners in cast-iron shell- 
ihese valves are made in standard sizes, and the name-size 
repr^ents the full-bore of the pipe to which they are fitted. 
Ihe elevation and Section No. 5 illustrate' a standard 






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HYDRAULIC YALVES AND FITTINGS. 



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249 



double-spindle lift- valve, which, being 
in its action. This valve is largely 
presses to be described later. 



balanced, is rapid 
used on stamping 



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No. 5 .-Standard Double-Spindle Lift Valve. 

The section No. 6 illustrates a patent hydraulic hose 
coupling for plain or wired hose, suitable for pressures up 
to 1500 lbs. per square inch. This coupling is made in 
standard sizes, and is extensively used. 




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No. 6.-Hose Coupling 



Sir William Arrol and Company, Limited 
great variety of standard hydraulic valves and 
those illustrated are only types. 



make a 
fittings ; 



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Hydraulic Stamping Press. 

FOR stamping plates to any shape to increase resist- 
ance to stress, to make stiffening Manxes, as in the 
case of water-tight bulkheads in ships. to form gutters, 

or to turn out corresponding sections. Sir William Arrol 

and Company. Limited, manufacture a special hydraulic 
tool, which is illustrated on the opposite page. This tool 
is made iii various sizes — the one illustrated takes plates 
up to i5 ft. in width, and of any length. There are 
three hydraulic cylinders suspended from the cross girder 
forming the top member of the built-up structure, and 
each in this case is of a diameter of 15 in. 

To the ram-heads there is secured a girder, which 
works in grooves formed by angles in the vertical members 
of the frame This girder compensates for any variation 
in pressure in the cylinders. On the bottom of this girder 
there is bolted the dies for stamping the plates. 

A\ Idle all three cylinders may he operated simul- 
taneously, a gun-metal cock has been fitted to each. ><> 
that any of the cylinders may he disconnected. In this 
way the total power to he exerted through the dies may 
be varied to suit the work in progress. Thus, with one 
lo-in. cylinder in action the pressure is 73 tons, with 
two cylinders L46 tons, and with all three about 220 tons. 
The working valve is at one end of the tool, with an 
actuating lever at each end tor the convenience of the 
operator. 



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work. 



Light Power Stamping Press. 

FT1HE illustration opposite shows a light power stamping 
press, suitable for sheet metal and other light 

There are two cylinders bolted to a vertical planed 
face on the built steel frame, and each cylinder is capable 
of exerting M) tons pressure on the dies.* 

One ram can be used for holding the plate while the 
other doos the pressing. The stroke of the ram is loin. 
There is a gap of 2 ft. to the centre of the cylinder, so 
that work of a bulky character can be undertaken. 









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Light-Power Stamping Press. 




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( 254 ) 



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Hydraulic Flanging* Press. 



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rjlHE machine illustrated on the opposite page is intended 
tor forming, by the use of dies, the rings or tianges 
of steel pipes rut out of a circular Mat plate. The 
photograph reproduced shows that the cylinder, which is 
a steel casting with gun-metal linings, is secured by 
brackets to four columns carrying the entablature. The 
diameter of the cylinder is loj in., and the stroke 3J in. 
In this cylinder there work two telescopic rams. The 
outer ram clamps the plate, while the inner, working 
within the main ram, and having a stroke of 11! in., 
turns down the metal to form the ring r flange. As 
a rule, two heats are required to carry out this work. 
The machine shown tonus flanges for pipes up to 14 in. 
inside diameter. 



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Portable Hydraulic Jack. 

ITIHERE is illustrated on this page an hydraulic jack, 
-*- with separate pan pump. This is extensively used 
for lifting heavy Loads. Although the total weight of 
the whole appliance is only 34 cwt., it can move 50 tons 
through !> in. As the jack is separate from the pump, it 
can be used in confined spaces, where the ordinary type 
of hydraulic jack could not be applied. 




Portable Hydraulic Jack. 

This portable plant is used for many varied purposes 
—for raising railway carriages and locomotives after they 
have been derailed, for straightening collapsed boiler flues, 
or for lifting heavy castings or girders into position, etc. 
The pump, which has a ram of ; in. in diameter, is 
worked by hand. The accessories to this equipment include 
a short length of flexible hose-piping, and two sets of 
gun-metal couplings. If bigh pressures are used, the 
connection between the pump and the jack is made by 
a solid-drawn copper pipe, 



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( 257 ) 



Hydraulic Press for Forming Knees and 

other Stiffening Units. 

rilHE illustrations on this and the next page show an 
hydraulic stamping press, originally designed for 




Hydraulic Machine for Forming Knee-Bars, etc. 



forming knees, angles, and other stiffening pieces in the 
beams and webs of gilders, but now very extensively 

applied in connection with corresponding details m ships, 

in locomotives, and many other manufactures. 

This stamping press* has a cylinder 14 in. in diameter. 
with a stroke of 18 in., and works at a pressure of about 
1000 lb. per square inch. The cylinder is mounted on a 
horizontal massive table. On the ram head there are forme- 
blocks, while secured on the table in front are corresponding 



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258 



im»i;\ri.l< PRESS 



dies. The bar is placed on the table between the blocks 
and the dies, and as the rain is forced forward by hydraulic 
pressure, the bar between it and the dies is squeezed into 
the exact shape required. The operation is expeditious 
and accurate. The whole of the metal within the bar is 
retained inside the knee, which becomes thicker and broader, 
and thus materially stronger. 

■ * 




Machine and Dies for Forming Small Units of Girders. 



U 



As the moulds or dies can be made to suit any form, 
the machine may be utilised in the preparation of various 
details of structure, provided they are designed with a view 
to their production by the aid of dies. With each press 
there are supplied dies and blocks to suit the special work; 
and as the firm have succeeded in applying this too] to 
a great variety of work, suggestions can' be given for its 
use in many classes of manufacture 



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( 259 ) 



Hydraulic Angle=Cutting Machine. 

rilHE illustration on this ]>age shows a simple and effectiv 
-*- hydraulic machine for eutthm angles for ship and brider 



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Cutting Bars and Angles for Girders 



building. The shear is secured to a ram working in a 
cylinder, controlled by a simple form of valve. The angle 
rests on the anvil, which carries dies to suit the shape. 
I|v changing the dies, any form or dimension of bar may 
be cut. so that the tool lias a wide range of application. 














■ 



( 260 ) 




^ 



i5o=Ton Electric Hammer=Head Crane 

at Clydebank Works. 1 

nriHE great development of marine engineering in recent 
times lias necessitated new appliances of special 
(lesion to facilitate the handling of heavy pieces of 
machinery, large cylindrical boilers, framing of recipro- 
cating engines, rotors and casings for powerful marine 
turbines, often weighing as much as 150 tons: and 
within the past two or three years what is now termed 
the hammer-head crane has in many instances displaced 
sheer-legs or jib-cranes. The earlier types had their 
origin on the Continent, and several such cranes of huge 
power have been erected in Germany and Great Britain. 
These have generally proved satisfactory in solving the 
problem of handling the large weights, although, perhaps, 
wanting in some respects in that solidity which is desi- 
derated by British ideas in the interests of durability 
and low cost of maintenance. 

Messrs. John Brown and Co., Ltd.. of Clydebank, 
have recently had completed for them two cranes of 
150-ton capacity — one on each side of their ritting-out 
basin— so that they may deal with the heaviest loads for 
two slops sinniltaneously without moving the ships to 
and from the crane berth, as is done in other work, at 

'The description of this nan, is reproduced I.,,,,, Engineering, vrol. IxxxuX, 
'"-' W, where fuller particulars and detailed drawings are published. 




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150-ton ELECTRIC HAMMER-HEAD (HANK. 



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considerable expense in time and money. One of the new 
cranes is of the derrick type. The foundations are steel 
cylinders sunk to a great depth, and these, together with 
the structural portion of the crane, were built by, and 
from designs of. Sir William Arrol and Company, Limited. 
This crane is placed on the east side of the dock. and 
has been used in the fitting-out of the Cunard liner 
" Lusitania." The other crane is of the hammer-head or 
Titan type, and is placed on the west side of the dock. 
It consists of a square tower, 125 ft, in height, and carries 

a horizontal jib of a total length of 240 ft., the hum- arm 
being 150 ft. in length. The jib is supported upon a ring 
of live rollers, and is capable of making a complete revo- 
lution in both directions, with lifting and racking motions. 
This is the largest crane of its type yet completed. 

The tower is formed of four legs, forming a square 
40 ft. on each side of the base, tapering to 35 ft. at the 
top, with diagonal and horizontal bracing of box-girder 
section between them, and supporting at the top platform 
girders to carry the roller-paths and live ring under the 
jib. The foundations of the tower are formed of four 
cylinders, 75 ft. long and 10| ft. in diameter. The bottom 
is belled out to U}> ft, in diameter, to reduce the pressure 
on the ground to 6 tons per square foot, and to form a 
working chamber for the excavation of the material. 

The platform supporting the live ring is constructed of 
four main box-plate girders, fitted between the legs of the 
tower, with short diagonal box-plate girders at each corner 
forming an octagonal frame under, and giving a continuous 
bearing to, the lower roller- path. The main platform 
girders are 71 ft. deep and 8J ft. in width, with a divided 
bottom flange, so as to permit of inspection and painting. 
rwo transverse girders, crossing each other at right angles, 



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150-TON ELECTRIC HAMMER-HEAD CRANE. 






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are placed between the centres of each parallel pair of 
main platform girders, to take the lower end of the centre 
pivot-pin. This pin is 14 in. in diameter and L3 ft. long, 
and passes through the cross-girders of the tower at their 
intersect inn. and through a box-girder secured to the main 
girders of the jib and the drum-girders. 

Access to the crane is obtained by a stairway attached 
to the diagonal bracing on three sides of the tower and 
leading to a platform round the top of the tower, formed 

-in. chequered plates, with a suitable hand - railing. 

From this platform, stairs and gangways lead to the 

jib-rail level and operator's cabin. 

The diameter of the track upon which the main girders 
rest is 35 ft., and there are seventy-five rollers in the live 
ring, each 14 in. mean diameter and 14 in. long. The rollers 

are forged steel, and are of conical form, and spaced about 
Hi! in. centres apart. Drawings are reproduced on pages 
265 and 267. 

The tracks are of cast steel, 2! in. thick, and are 
brought true by packing-plates and folding-wedges, which 
are inserted between the bottom track and the tower- 
girder, and between the top track and the annular bearing 
.under. The circular slewing rack is of 5* in. pitch, and 
is bolted to the palms east on the lower track. A check 
w formed ,„, the rack, and tour forged hooks bolted to 
the annular bearing-girder, and revolving with the crane, 
engage with these checks, so that any possible upward 
novemeni of the girders, caused by the singing of the 
load, is prevented. 

The jib is constructed of two open-lattice box girders, 
14 ft centres, the distance between the webs of each 
boarder being 4 ft. The girders are 26 ft. deep over 
the tower, 7 ft. at the end of the long arm, and 1. 5 ft. at 



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l.")()-To\ ELECTRIC HAMMER-HEAD (KANE. 



the ballast-box. The form of girder adopted was the 
open ••Warren'" type, with intermediate vertieals from 
the intersection of the diagonals at their lower extremity 
to the top boom, thus breaking up the long panels of the 
top boom into smaller bays, to resist the severe hendin 
stresses due to the concentrated wheel-loads of the jenny, 
which are additional to the direct tensile stresses as a 
cantilever. The box-girders are connected together at 
the end of the long arm by a stiff lattice frame, which 
carries the brackets supporting the horizontal girders to 
take the jib-bead gear. From the front of the roller- 
path to the end of the short arm the two main girders 
are securely braced together, both horizontally and verti- 
cally. The ballast-tanks at the end of the short arm are 
tilled with 86 tons of nickel slag concrete. Raking struts 
are placed between the centre vertical of the jib and the 
drum-girder, to transmit the lateral wind stresses to the 
tower and increase the lateral stability of the jib. The 
jib-girders are secured to the drum-girder by large gussets, 
of ample dimensions to resist the severe torsional stresses 
due to the sudden starting and stopping of the jib. Four 
lines of bridge rails are provided, one over each web of 
the box-girders, and they are riveted to the top flange. 

The machinery is placed in a house formed of steel 
plating at the tail end, and assists in counterbalancing 
the crane. The speeds of the various moti 

■ 150 tons at 5 ft in. per mini] 

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Auxiliary lilt ... ., n 



ons are as follow : 






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Racking 



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40 „ M 
100 „ „ 
One revolution in 1< * rninui 

Messrs. Stothert and Pitt, Ltd, Bath! under a sub- 



150 

30 

150 

30 



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1 50-TON ELECTRIC HAMMER-HEAD CRANE. 



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contract supplied the mechanical appliances connected with 
the lifting, racking, and slewing motions, together 
with the large travelling jenny, jil> head-gear, ropes and 
snatch-blocks, with all working levers and equipment for 
the driver's cabin, and with all the collectors, wiring, and 
other electrical work on the crane. 

The official test of the crane took place on April 24th 
1907, and was in every way satisfactory. The test load 
of 1(5(1 tons at a radius ,<f So ft. was raised at a speed of 
4.8 ft. per minute, and lowered by moans of the hydraulic 
brakes, and successfully held by them and by the magnetic 
brakes independently. One revolution with this load at 
85 ft. radius was made in :,', minutes. During the 
process of raising the load, observations were mad., of 
the vertical range of the vibrations by means of a wire 
SU8 Pended f, the jib to a recording apparatus on the 

ground. The range varied from ,; ; in. to j in The 

maximum deflection at the end under this load was 

<>: m., while the tail end of the jib rose 3A in. Under 

80 tons load, at 133 ft. radius, the deflection was 7< in. 

With 30 tons load, on the auxiliary lift at the end of the 

•J"' fche crane made one complete revolution i„ 3 minutes 

seconds giving a velocity of nearly 300 ft. per minute 

a the end of the jib. The crane showed great rigidity 

and stiffness. The swing of the tower under the racking 

1 Wtwg tests, and the twisting of the tower under the 

'""' ' M1 - 1 -' l «"'.iib. were hardly perceptible. 

'<■ satisfactory completion of this crane is very 

1 i <■< n table to Messrs Si* Win- 

Ltd ,,„i af William Arrol and Company, 

S ' b ii j ^ eSSt&S ^ fchert and Pitt, Ltd. .t demonstrate, 
desL and "T*?"™ ■» -ell to the fore in the 

ma mi / C "" Stn,,t "" 1 ° f ™* <* this special class and 












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270 



150-TON BLECTRK HAMMER-HEAD CRANE 



We append Sir William Arrol and Company's standard 
specification for the structural portion of heavy cranes:- 

Wind Pressure. 

U) Crane not Working.— The wind pressure shall be taken at 501b. per square foot. 

\b) Cram Lifting Working Loads Causing Maximum Stresses.— Wind pressuii 
shall be taken at 5 lb. per square foot. 

(c) Crane Li/ting Test Loads. -No wind pressure assumed. 

In all cases the wind pressure shall be assumed to acl on a surface equal to U turn s 
the area of the surface seen in the elevation. 

Momentum, Impai i. &c. 

The stresses caused by the slewing and stopping ..f the .jib, the lifting and racking 
of the various loads at their respective speeds, the effects of the brakes, &c, shall 
be provided for in proportioning the sectional areas required for all parts of the structure. 

Maximum Permissible Stresses under Dead-Load and Full Working Loads. 

Jib and Tower. -The maximum stress shall nol exceed »'•! tons per square inch 
on the net section in t «- 1 1 — i ■ »n or compression, hut in no case -hill the member in 
compression be subjected to a greater stress than one-fifth the ultimate strength of 

ilic member considered as o column. The stress on tin- rivets -hall not ex< 1 5 tons 

per square inch in shearing and 10 tons per square inch in bearing. 

In members subject to stresses from wind pressure only, the stress shall not 
exceed 7 '. tons per square inch <>n the net section in tension or compression; hut in 
no case shall the member in compression 1»- suhjertrd u< a greater stress than one-fourth 
the ultimate strength "t' 1 1 » « - member considered as a column. The stress on the rivets 
shall not exceed <> tons per square inch in shearing and 12 tons per square inch in bearing. 

Alteknatixg Stresses. 

Members subject t<» alternate tension and compression shall have sectional areas 
equal t<> the joint areas for the compressive and tensile stress ■> considered inde- 
pendently, except in the case of wind-bracing, where the additional sectional an 

may be one-half the preceding. 

1'. i.m 'in«. Stresses. 

Where a bending -tress occurs on a member subjected to a direct tensile or 

compressive stress, the sectional area shall he proportioned to the sum of the stresses 

Rollers. 

The pressure m pounds per lineal inch of live rollers shall not exceed that given 
by the formula 300</, where d = diameter of roller in inches. 

•I'.in rs in Memiikk>. 

Tension, 'hunts in tension members shall be fully covered and riveted to resist 
the maximum tensile and shearing stresses transmitted through the joint. 

i'umprfittsinn. The butting ends of compression members shall hear through their 
whole faces, and be covered and riveted to a sufficient extent to transmit at lea 
one-third of the thrust as a shearing stress through the rivets. In plate-girder I >p 
booms the proportion shall he two-thirds. 

Sectional Arras. 
In estimating the sectional area of the flanges of the jib, the tails and flo 

plating shall not be in.lude.l in the area ; for net sections the diameter of the 



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rive( - holes shall be taken as 4- i r 

Hang, area. MU " ( *• web „l,t, .,,,,„ ,„. ;„,,,„,,„, . _ £ 

T , Foundations. 

Ihe pressure <„, the concrete shall n t 

irking loads and wind pressure. ' " " X ''' 10 *"■ l )er *i»™> foot under th, 

in . Constructional Details 

All members shall be designed of such ( 

P^MUft and to allow a free circulation of \T ^^ ^^^ f '»' inspection 
To alio* f 0I corrosive .„„■.,.,„,., „ " ° f air *""* the """">- 
"ear the ,. , „„ ftngIej ^ Qr ^ JJ^f <* "J*"**? districts and 

1- minimis,- vil, ration* ,,,,1 , , . •, ItSS fchlc knes S than 3 ,„ 

- « ■ m *.„;,.; "^'i; :;;t7 ial r *" " ; ■ ■! S— 

"* ' Nsonal bracing of the towe , ,1, 7 " S te " si °" ° r """!—, 

TLe ,1,,,,,,,,,. ,, L roller^ "'? T ""'*'"" """"'^ "" K ' 

loading, the centre of gravity o „ , •, ,"""' "'"''•'' :,il «■**■• of 

-* - » r ■—** h,,:i::,.,:;;; . .tt'ir " ot "" ! " ■ »■ 

„ f the frim(i 8 bare to nuuntaro the relative motion „ f „,,. |K „. [s 

*■£ E^V^J"!5 ;;'"' '. ; 8ta,ction » ( ■ — « ■ 

<" •■*« a vertical ,„, ri ' , , '1 gUdera u "" n "- jt > sl "" '»■ designed 

load lifted i„ „,..:,,;:::. n/ - nuA to ™ uf »< ■— *»** * & ,,,,„;, 

f, utnT "' fte '"""' '" Pbn Slla " '"■ « h »* »» *-*» shall exis. in the 

-Mammi-m PmanmmM Stbjbsm kmr TM Tbst-Loads 

b£s?3Lrii e fferent ■?*- ° fth ° jib and tower *■■ - 

25 per cent. '"''' ""'""'" WCh " xct ' e,ls the s l" ! ' ili '" 1 *■— °J 

Materials. 

l',v„,. ; ; „ „ ','' B ^' '7'" h > " l " * "-Martin »Pen-hearth acid ,,, 

of a,",,,. • '' 9tre f ngth ° f f '""" " 7 ( " 32 *« P- -1"- inch, with an el„,,,„M, 

' l -° l" r '•'"'■ '" a length of » in. 

,,,,,;,;;;' '''J 1 ^ •»»■ • >""sion,d ,„,„ g th of 26 to 30 ton. per square inch, and 
""""""" el.a.^uion of 03 ,„.,. ce „ t jn a ]ength rf g jn 

^"1 steel shall be practically free from Mow-holes and other defects, and is to he 
in an cases, and have a tension*! stn-ii K t)j of from 27 to 32 tone per square 
■". Wth an elonoation of 13 per cent, in a length of 8 in. 

Workmanship. 

tians t, I i'' "' thP Un,kmanshi P shaU ,,e of the highest class. Where stress is 
If v '"" M ( the beared edges of plates and bars shall be planed, and all holes drilled 
com . '"' P° w er-rivefcing shall be used where practicable. The abutting fares of 
J :i -•'"»' members shall he marhim-,1 after the section is riveted, so as to ensure 
perfect """tact on the abuttillg surfaces. 



-^>* 



."V.-R 



( 272 ) 



Electric Derricks for Shipbuilding Berths. 



.< 



t 



c 



* 



*I< 






rflHERE are illustrated on opposite page electric derricks 
^- of great height, which were constructed for use in the 
building of the express Cunard liner "Lusitania" at the 
Clydebank Works of Messrs. .John Brown and Co., Ltd. 
This ship, as is well known, is the largest that has ever 
been constructed ; and. in view of its great height, it was 
necessary to arrange for exceptional derricks. 

These were designed to lift a load of 5 tons to a 
height of 120 ft. from the ground level, with a working 
radius of 35 ft. from the centre of the mast, and with a 
jib slewing through 180 deg\ The mast is constructed 
as an open lattice-work column of square section, with 
four cornel- angles, well braced together. It is (> ft. 
square at the central portion, and tapers to IS in. square 
at the ends. Four g UV s are attached to the top of the 
mast, and one underneath the jib. A platform tor the 
electrical gear is arranged at a height of 95 ft. above 
ground level, and from this point there is carried the jib, 
which is rectangular in section. 

The jib is set at an angle of 45 deg., and at the 
outer end there is fixed the usual pulley for the 
lifting rope. This rope passes over a deflecting pulley at 
the base of the jib, and thence through the centre pin 
to the electric winch located on the ground level. 

_ The electric motor, of 30 brake horse-power on the 
winch, is arranged for two speeds of lifting— 90 ft. per 



C 






<c 



IlVC 




If Berths. 



v in ■ 



[| a 



gin! * 
i v fa 

el 

,wer 

■ 







Electric Derricks for Shipbuilding Berths. 



NN 



■ K?a 





274 



ELECTRIC DERRICK FOR SHIPBUILDING BERTHS. 



minute and 210 ft. per minute, the former being for the 
full load of tive tons. The slewing motor is placed on 
the working platform, 95 ft, from the ground level. 

The view shows two such derricks, built one on each 
side of the Cunard liner, the double bottom of which is in 
process of construction. Six riveting machines are shown 
at work on the double bottom, all of Arrol's make. 




R 






*v 



' 



5 



( 275 ) 



% 



Compressed=Air Plant for Sinking Piers 

and Shafts. 



IjIEW films, if any, have done so much work in the 
sinking of bridge and harbour piers, etc, under 
compressed air, as Sir William Arrol and Company, 



«j 



crr^LJ 



~\ 



,_ i 









Sinking a Pit Shaft by Compressed Air. 

Limited. In the work of siting the J^.^% 
pier* of the Forth Bridge, of the 10,500-ton g» tf*J 
Wear Bridge, of the 117-ft. deep piers of the Banc, 
Bridge in Ireland, as of n.an.v e.ua y g^J— 
great experience has been won ; and tins PI 




.^» 






.< 



1 

c 



276 



COMPRESSED AIR PLANT FOR SINKING FIKRS WD SHAFTS. 



^ 



the plant manufactured at the Glasgow Works for such 

operations. 

In recent years the system lias been extended for almost 
all kinds of inundations. As illustration of such plant we give 
on the preceding page a view of the sinking of the Stevenston 
pit-shafts of the (Viengarnock Iron and Steel Company. 

Two shafts were sunk near the foreshore through beds 
of sand, shells and clay, to the rock found at a depth of 
84 ft. from the surface. The shaft was of steel 17 ft. 6 in. 
in diameter, lined with brickwork '20 in. thick during the 
process of sinking. Here, as always, special details had 
to be devised to meet unusual conditions ; in this instance, 
a sound water-tight shaft was of great importance, in 
view of the proximity of the sea. 

The photographs reproduced on the opposite page show 
the form of lock made by the firm for use in connection 
with air work. The lower man-lock has two compartments. 
It is semi-circular at the ends and flat in the centre, and 
has capacity for three men in each of the two compartments. 
The lock is built up of steel, the flat portions being 
stiffened with beams and angles. The doors are steel 
castings with rubber joints. Bulls-eye glasses are provided. 

All the joints are caulked, and the whole is tested to 50 lb. 

per square inch. There are air-cocks to enable the workmen 
to regulate the pressure-air when passing from one com- 
partment to the other; the outer space is used as an 
intermediate stage in entrance and exit. 

The material lock is placed above the man-lock. 
The doors in this case are horizontal, and are opened and 
shut by a hand rack-motion, worked from large hand 
wheels. There is provided a small steam engine for 
working the winding drum. In order to throw this lifting 
drum out of gear quickly, a clutch is provided, so that 



! I 

v ! 
OIQ|KUiy. 






I 



I 1 















. - 



uparti 
rkmen 









V. 



j m 



em.* 



COMPRESSED MR PLANT FOR SINKING PIERS AND SHAFTS. 

when the buckets are resting on the bottom door an 
overhead lifting arrangement may be brought into gear, 
and the buckets raised above the lock to tip the excavated 





Air Locks for Sinking Foundations. 

material into the shoot. The only additions required to 
complete this installation are the boilers and air com- 
pressors, with connecting pipes and fittings ; and these 
also are supplied by Sir William Arrol and Company, 
Limited. 







.^» 



& 



(si * 





• 



r 



* 1 35) 

t 



a. 



( 281 ) 



FORMULA AND DIAGRAM 



S 



FOR THE 



CALCULATION OF BEAMS 



N< «TE : 



in modulus 



(i) Expressions containing E annlv «mlv *.-. i 

of elasticity. l J nl> fco beams and cantilevers of unifor 

''''^i^^ ientof 

{m)Ml ^^^ 

modulus of ete&V ^eonstanl moment of inertia and uniform 



CONVENTION (iF s„;xs AND NOTATION C7SED 

In all cases the origin is at the left-hand support. 



THROUGHOUT. 



1. 



J. 



3. 



Diagram showing Method of Loading: 

+ x measured horizontally from left to right. 
+ y measured vertically downwards. 

Shearing Force Diagram: 

Start the diagram from the origin. Draw reactions vertical 

and upwards: applied loads vertical and downwards. 

Bending Moment Diagram: 

+ M downwards when it causes convexity downwards. 
— M upwards when it causes convexity upwards. 



» K 



oo 






.^** 



^JS 



282 



FORMULA AND DIAGRAMS FOR THE CALCULATION OF BEAMS 



I = Spun. 



W = Total Load. w = Load per Foot. 

M,,. Ma, M b Bending Moments at 0, A, B. R„. I»a. 1',; Reaction* 0, A. U. 

E = Modulusof Elasticity. I = Moment of [nertia. 

Expressions involving I apply only to beams having a constant Momenl of [nertia. 



H\ Cantilever Load at one. 
end 



Si STEM OF LOADING 




SHEARING FORCE DIAGRAM. 

B 




OB-W 



BENDING MOMENT DIAGRAM 
B 




OB-W I 



lio.r) 



(I) 



Ro - W 

slicaring finrc between and A = \V 
Bending moment between and A = — W [l 



M.. = 



n 



\\7 



Equation fco elastic line : 

Wr- 
it = 



6 E I 



:;/ 



-.) 



I Reflection al A = 



TO* 
3 El 



( 



c 

1 

3 



M 



< 



(2)Cantilcver loaxiurufcrmly 
dis Irib uted 



SYSTEM OF LOADING 




1* 1 _ 



-*A 



SHEADING FORCE DIAGRAM 




QB-wl 



BENOlNG MOMENT DIAGRAM 

B 




ABieaparaboUtwOh vertex at A 



(2) 



R„ = w l = W 
Shearing force between and A = m>(/ - x) 

Bending moment between and .V = «- 

id* 

Mo = - T 

Equation to elastic line: 



] ><'fU'<'tinn :it A = 



W/8 

8EI 






R 






«, 

£> JZ 









**lM 



■ I 



-w 









loRMLL-E AND DIAGRAMS For THE CALCULATION OF BEAMS. 



283 



Spill. 



W = Total Lead. 



Mo, M A1 M B Bending Moments at < >, A, ]:. 



w = Load pei Foot. 
R,„ K A , R B Reactions it I », A, I>. 
E = Modulus of Elasticity. I = Moment of Inertia. 

Kx|.r.->sions involving I apply only to beams having a constant Moment of Inertia. 



I® 



^ (UvTtJbLever.locLcL usu/brrnZy 
xjiercasinx] towards support 



SYSTEM Of LOADING 




SHEARING FOPC£ DIAGRAM 

B 




OB-W 
\Bucl paraJbola, with vertex at A- 



BENDING MOMENT DIAGRAM 

B 




OB^ 

ABiscLCubic withverteJcajbA. 



(3) 



R = W = Total load 



■1 W 



Intensity of load between Dand A =* — 1 1 -,■ \ 

2~\\ 
Intensity of load at = 



I 



Shearing force between and A = 



\Y(/ - xf 



Bending moment between < > and A = — 

3 /-' 

M = - _ 

Equation to elastic line: 

y = { . {)VA/ ,{\0!-'-- 10l*x + 5lx*- ..■■■'■) 

1 Reflection at A = , • 



■ 















(fi\BeajTv. oentraL XocvcL 



SYSTEM OF LOADING 

o \vr b 



SHEARING FORCE OIA GRA 14. 

Cx 











1 




l J) 



OC-BD-^ 

3m 



BENDING MOMENT DIAGRAM 

A B 




ten 



o) 



w 

■i 






w 


Shearing force between and A 


= 2 


I 




Bending moment: .'• ^ ^ 




Wx 
M.- 2 




M„ = M„ = 


M A 



m 

4 



I 
Equation to elastie line : X < 2 

7 _ 5* r^ - «*] 

•" - 48 EI L J 

Deflection at centre = 4gEI 




^># 







lV 



& 



.< 



^7; 




i 



s* 






284 



FORMULA AND DIAGRAMS FOR THE CALCULATION OK BEAM-. 



I = Span. W - Total Load. w = Load peT Foot. 

M,,. M A , .M,. Bending Moments a! « ». A. B. If,,. l.\, R B Reactions at ( >. A. B. 

E = Modulus -I' Elasticity. T = Moment "I' Inertia. 

Expressions invoh ing I apply only i" beams having ;i constanl Moment of [nerti 



J^Be/xm,. lecuL at any point, 



SYSTEM OF LOADING 



R 



o \w 

F 



b -— 



]** 



SHEARING fOBCE DIAGRAM 




oc-Zl 



BD- 



Vr r a 



dTB 



BZN DING MOMENT DIAGRAM 

A B 







(jj)Beam uniformly axstrib^ 
' load,. 



SYSTEM OF LOADING 




SHEARING FORCE OlA GRAM 

c 




oc-sn -$£ 



BENDING MOMENT DIAGRAM 

A B 




OKB Cs a parabola withvertejc 
*tE 






\\l, 



l: " a + I 
Shearing force betwrni u ami A = I.',, 
Shearing force between A and 11 = I!,, 
Bending moment : 

Wbx 



Rb = 



Wa 

a +~6 



(i) ./• - ,i 

tiii x > a 



a + b 

Wbx 
M.= r - \V(z a ) 



a + h 



M. 



\Xab 

1 + <> 



Equal ions to elast ic line : 
(i) x - a 

Wbx r , -1 

1 11 1 x ;> a 

y = g K| (i ]\ f>) [(■'■ - a) 3 - 3&b 2 + l'/,-V + 4a6x - a 8 o] 

WW 



Deflection at A = 



3E1 (a + b) 



I Reflection at centre a U b = 



Wa 



(3o s + 6ai a?] 



is EI 
Maximum deflection : 
(i) a > 6 
, Wa6 (a + 2 6) 

','„ ~ 9EI(a + b) \/ a l±l^ aI I"' n " w «ere ..■ = y / g» + 2«6 

3 3 

(ii) <* < 6 

>ccurs a1 point where a; = a + h - I //-' + 2a6 



max. 






(6) 



K = R K = — 



siu-aiin- force between and B = - (l - 2x | 
Bending moment : 



wx 

M ' = T 



(*-.) 



M A = + 



Mo M B = 
Equation to elastic line: 

.'• - -2/.,' + 

5 

384 EI 



~8~ 



// = 



,/■ , 



24 EI 

- 

Deflection at centre = 









- 









y 






"" ;M, '- K AND DIAGRAMS P0 R THE n„ 

" "«E CALCULATION 



°F BEAMS. 



■«..M,.M„.- 7 '^.M..,...-n,.., I „..C,r l "' a ' 1 ' -U„l Iwroot 

«- Modulus of EUMttat/. , *• E * »» Reactions at A B 

Ezp.ess.oos invalvi,,,, | spplj ,„; |v ' - Moment of Inerti* 

S^^^ '""'"^ ■*•** * of Inertia. 



i' s ;, 



OS? 



SYSTEM OP LOADING. 



centre 




*fc£l. * > 




oc-bd-Y ^ 

with, verdicas clLA 



BENDING MOMENT DIAGRAM 

A 




HBM^L 




SYSTEM OF LOADING. 

A 




SH £*"'NGFO*CED,A G R AM . 

c 

_ 
OC-BD.Y 

U<M)as.e pc ^J ai _ 

B£nd7 ^^^^t~l^a~g~^a~^ 
A B 





** mf M" 



Intensity of load at = £2 

^tensity of load between and A = ?_^j-_?£) 

Shearing force between and A -J* ft* 4/ ml 



Shearing force at = - 

2 

Bending moment : * < L 



Mj = !ia[ 4 ' j - g ^ + 3/J 



Mo -M»- «. 



M, = 



Equation to elastic line; , < £ 



12 



.'/ = 



AY 



480 EI 



Deflection at centre = ~^' 



J/: [- 16** + 40&>-40fU + I:./' 1 



320 EI" 



Intensity of load at A = 



2W 



'"'""siiv of load between Oand V = 4Wx 

P 

8hearing force between and A = M , ( /- _ 4 # I 
Shearing force at = — 



/ 



Bending moment: #< — 



w; 



War -1 



Al„ - M 1; = 






\\7 



Equation 1u clastic line : X < - 

~~ 2 

^ = 480E[/{ 1C ^- 40/V+25/J ] 



I Reflection art centre = 7 



tiOKI' 




.^: 



286 



FORMULAE AND DIAGRAMS FuK THE CALCULATION OF BEAMS. 



W 



& 



< 







r « 



c 







/ = Span. W = T<»tal Load. to = Load per Fool 

M ( , M^ M fl Bending Momentsat O, A. B. K (( . R A , R B Reactions 0, A, B. 

E = M. Mlulua oi Elasticity. I = Momenl of [nertia. 

Expressions involving I apply onl) to beams having a constant Moment of rnerl 

Total Load = \V 

2 W 
Intensity oi load at I I = 



TtsuforTrtCy tow cerate orte erwL 



SYSTEM OF LOADING 




3* 



(9) 



/ 



SHEARING FORCE DIAGRAM 

B 





V 



QB-fW ADJW 
0C--4231 

BCD is a-parabola with vertex alD 



BENDING MOMENT DIAGRAM. 

C ^L 




0Ct23iCI)-mWi 



.Curved, beam Root Davit. 
— cut* atji 



SrSTEM OF LOADING 



c 



SHEAR JNC 




A \Ra 



w 

A 




G FORCE DIAGRAM 



F l> h 

CL- o . 

Vertical or denotes 
B\ .// betoeen.E&C'Yr 

EGCE-W 
EH AKH B 

A CEls neutral lute 



^^f*E 

c Jo 

BesiUtng Moment, 




H 



increases uru/brmW 
between, E& C ^ 

4 CGBH-WL 

A CE is neutral lime 



" \\ il 

Intensity of load between < > and A = 

Shearing force between and A = - — T f :; ..-_ i. .. 2F~\ 

2 W 
Shearing force at = 



3 



Shearing i*urce ut A == - 



5 
~3 



Bending momenl : x < I 

M * = 3F [" " :i lx + - 

M„ = M A = 
Maximum bending momenl = .128 Wl 
where ■>■ = A 'I'M 

Equation to elastic line : x<l 

W r. 
y = 



4 7 WP 



(10) 



Maximum deflection = 
where./ - .48 I. 
R. = W 



■■:«:00 EI ' 



H A = H B = 



\v/ 



Shearing force between E and C W 

Shearing force between Band A - II„ = H. 

Shearing force down < 'A = W 

M, =M A =0 . M, - M B = Wl 
I Reflection : 

wi I/'V' Sli !}r dU >' ^determinate Structures," bi II. If. Martin, 
"h. &c. (page 36; 1895). 



^^ 



R 



w 



KOMMlL-r. AND DIAGRAMS l-OR THE CALCULATION OF BEAMS. 



287 



rru 












, H-3L1A 



SYSTEM OF LOADING. 

oL^aJe — J & 



(11. 



/ = Span. N ^ = Total Load. "• = Lwl p'-i Foot. 

a, at m Bending Momenta it 0, A, B. K,„ H A , II,. Reactions at 0, A, B. 

g = Modulus of Elasticity. I - Moment of Inertia. 

Expressions involving I apply only to beams having a constant Moment of Inertia. 

r, = : ; (• + 1 .) . k, - g i ». ♦ 1) 

landing moment : 
(i) x < a 

(ii) x> a and < (a + 6) 

M.- jfj {*•(* + 2c) -/(*- *)*} 

(iii) x > (a + 4) and < (« + b + c) 

M.,. = '" 6(/ ' s ;; 3 " , {4^ + M6 + 2c)} 

2/'/ + h (6 + 2 c) 



SHEARING FORCE DIAGRAM. 

D „„„,.. 

C 




OD-Ro CE-Rc 



RENDING MOMENT DIAGRAM 

-A D B C 



M 



wab / . n \ 




DzsrwuL point cfJlB. , 2 

DE>$ hcLtbtfb tzcX DF- %* 

Transfer- par oho La,Jkb*J5 to 
bcLseGM. 

m 



mux. 



at point where x = 
Equations to elastic lint* : 



•ii 



Let{2« 2 (6 + -JO + *(4a+5 + 4c) + 4c*(2a + 6) + 12afc) = m 

(i) -' • " 

v - "' /m ' '(»«) -2 a? (6+ 2c)) 
y 24 EK l j 

(ii) a > a and < (a + b) 

„ _ * h(~ - aY-2bx*(b + %c) + bx(m) - 
y ~~ 24 Ell I ; 

(iii) x > (« + 6) M»d < (a + 6 + a) 
Interchange • and c in equn. (i) for y, and measure « from * 

Deflection at .A = ^y^, {'' < 4 " + ° + * C) ' 

^ fl ,- M , "'^ f^(4a + 6 + 4 C ) + 4^(6+2c)+ L2a*c] 

Deflection at 1> - „^ g^ [ ■ 

Maximum «U-tl-«'tion: when it occurs for 
(i) .<•<« 



A _ _~— / ""^ afc P° illt Wh6ie '' = V 

36 SU V 



6(6 + 2 c) 



G(t> + 2 c) 

(U)X ?r nd .lmt/L-a)»-66^(A + 2c) + «6 = Oand 

,. s found from + ' <•' « / f 

8 by BuVstituting * m equation (u) for y. 

(Hi) ,.• > (a + 6) . / ~" 

«•/,/// /___!!! a tpointwli«iv.<=/- V 



it, 



ft 






as 



^ 



.^>* 



V 



T^ 



&< 



& 



V* 









288 



FORMULA AND DIAGRAMS FOK THK CAUTLATION OF KBAMS. 



I = Span. W = Total Load. w = Load per Foot. 

M„, M A , M B Bending Moments at 0, A, B. R , R A , R B fractions al 0, A, l; 

E = Modulus .of Elasticity. I = Moment of Inertia, 

Expressions Involving J apply onty to beams having a constant Moment of [nertia 



fp^jleajrv paj'tinlfyr le&ct&cL 
^ at thje eruls. 



SYSTEM OF LOADING 




SHEARING FORCE DIAGRAM 



O 




annak 



n 




OD R AE-R -R C CF-R C 

BENDING MOMENT DIAGRAM. 

DA BFC 




kiT — kg 

\Dis mxct point oTQAt. F of BC 

J)f->H f 2 I'GR C $DL^ 

I'M *y£ Trans fer par-aiolcLS 

PL A a BMC ' to bases OHsKC 

respectively 



(j^Bearrv: two symmetrical 
concentr-ateci Locuds. 



SYSTEM OF LOADING. 

Mfc=zJBL=t>. &c 



SHEARING FORCE DlA GRA M, 



D 





A 



B C 



K 



od-ce-w 



BENDlNB MOMENT DIAGRAM 

A B C 




R t: 

AD RE Wa. 



(12) 



fl -f f 



■) - *, ,?"" / -' +° I 



Bending moment : 
(i) x^a 

M, fix 2 " 1 " rt "' + c2 " lx ) 

(ii) .'• > " and r^j (a + &) 

M, = Yi | ■'■<•-" " J ) + «'} 
(in) .<■ > (a + A) and < (a + 6 + c) 

M, - Yl I''' - "'-' + 2«0 - l(x - a - 6 

M A , 1} [ab + ac + <-' J M |: ^jlac+bc + a 

Equations to elasl ic line : 

Lei fa 4 + c 4 + I ,/ ; (A + c ) + 1 ■ (a + /-i 1 = 

4 a 2 J 8 + 2ftV + <;<■- + ta6c(2a + -•>' = 
(i) .-•-2« 



Mi 



" 



y = 2i m [ ;,, ' : + - ' '" ■ 2al - «■) + (* + ")] 

(ii) (.-• - a and - (a + 6) 

factional A gj^jj { (m + ») - a 2 (a 2 + 2 c 2 ) 3a (6 - c)] 
Deflectional B = ..,Vl/{ (»+»)-*(* + 2«*) 3. ■ *«)] 



("i) •'• • (« + A) and < (a + A + -•) 
[Q terehangea and r in <•,,„,,. ,,, f or y, and measure a; from c. 



(13) 



R„ = i;, w 

pending moment between <> and A = W./' 
Bending moment between A and Ii = Wa 
Equations to elastic line : 

•'- = « ■ y = Jg(- a ?_3a :: 



./• 



Deflection at centre 



6 EI 



I'-il.-.-tj,,,, ;il ^ or B = 



2 I E I 
Wa 8 



($P- la*\ 



6E1 



f 



3 1 - 4 a ). 






Ci 



0' 



{ 

i 






I 















"" ,;M "-' ; **» KUUia Kn|1 .,.„„ 

CALCtTLATIOH M ltla , K 

M. M. Mending Moment, at 0,^3^^ 

'.'■ = Mo ' lu,us of Elasticity. , > Ra, *« Reactions at O V p 

Expressions involvin g I apply only to beams havin* . = ^ ° f Inertia - 
(^•am-a^w^er^- 1 ,Kn In 8 ■ constant Moment of Inertia 

^concentrated. Lead a 



SYSTEM OF LOADING 



(14) 



l; 




SH pl^ N6 F0RCE D,A G(fA *■ 




O A 

OE-R AF-J^-W.BG^WrW, 

C&R W A W B w e 



BENDING MOMENT DIAGRAM 

Q-A_ BCD 




AE=M A BF-M B CG-Af c 



80* 



W B 



s vs T£ *^of~l~o~a~o7n~s~. 




SHC ^f^oRcr 7A~^j M -^ 




OC-BD-Y 



c 




°C-£D*AE*lp, 



w I- a lh 

/ +M »~f + W icf +itaL 

/ T U,! 7 +W C + e tc. 

M = M D = o ' 

I).f| f ; 'ii.lsoon. 

construction may be used (V&* % j , fl, ' ,t,ons ; "r a -mp],i,-,i 
peering,' >„. ,,'- fc m i t , I ^KI! l 7. , :; l , ; , * " - M -'— - ^.pli..., jl! 



(15) 



Ro = Bb = J 



/ 



Bending moment ; x < - 



Mo = Jj„ = _ 5? 



Ma - + 



wv 



Equation to elastic line : .*• < - 



-' 



'' 48 EI 



(3/ - 4 a: J 



Deflection :tt centre = 

. , 192 EI 

i'oints of inflection ; 



or -l 

4 



4 






PP 







( 



53 



r<5r < 



290 



FORMULAE AND DIAGRAMS FOR THE CALCULATION OF BEAMS. 



/ _ Span. W - Total Load. w = Load per Foot. 

M,„ M A| M B Bending Moments at <>, A, H. Ro, ft* K„ Reactions al 0, A, li. 

E = Modulus of Elasticity. 1 = Moment of [nertia. 

Expressions involving I apply only to beams having :i constant Moment of Chertia, 

w 



(fiftBeam, encastered. at both. 
ends. locuJ. aJL any point 



SYSTEM OF LOADING 




SHEARING FORCE OS A ORAM 

C\ 



o 




\B 



I) 



0C-R o BDR 



BENDING MOMENT 01 A GRAM. 

O D AE B 




OLBis diagram^ For beam, as 
if Simply supported,,case. 3 

A P'%$ 00-M.BB-M, 

\A£MA_0XB'is base Line. 



(Ifi) 



II,, = ( ( 2tf»- 3cr/ + /) 
B. ™(5I-I.) 



m = -T'v-r 

I m - 1 n 1 i 1 1 i_r mi iHh'iit : 



M 



(i) x < J 
W 



r \x (2a a - 3a 2 J + / ; ) - a£(a - If] 



(ii) .<• ■ a 



-M, = /; " [.-(2o - 3/) /(a - i'/)l 



Equations i<< elastic line : 

(i) x ^ a 



y = 6EI/ : [~ •' ( -" " 3 " J/ + /:I ) + :U/ <" - l f\ 



(J El/ 
(ii) ■'• ^ a 



y = ,. ,,-iV[- ft <-- ,;: - 3 ' 1 ' / + ' > + :i ' 7 "• s ] 



6 El/ 

I»»-tl«'«'tioii :ii A : 






Maximum ili'tiWtion : 

(i)a<i 

_ -* W, r ,7 a )3 , / 

3 El (37 2^' at point where x — _ 

(ii)a>£ 

; _ 2W(« - /) ,; . , 2oZ(fl - /)'"' 

3 El , -i j-- 3 an + / r ' ;,t pom1 where '' = •->„- ^.iTTT 

Points of inflection : 



<>!> = 



a£ 



2a + J 



OE = 



/ (2 1 - a) 
3 J - 2fl 






*<$ 



»v 



MOi 






> 






- 







- 






* 



FOKMl'L/E AND DIAGRAMS FOR THE CALCULATION OF BEAMS. 



291 



I = Span. 



■\V = Total Load. 



M v M.. Mo Bending Moments at ( \ A, B. 



w = Load per Foot. 
][,,. R A , K„ Reactions at (>, A, 15, 

E = Modulus of Elasticity. I = Moment of Inertia. 

Expressions involving 1 apply ""'y t° Warns having a constant Moment of Inertia. 

a-} 



fftjieam-encasterexl atb 



SYSTEM OF LOADING 



'wlhendi «i 



) 




SHEARING FORCE DIAGR AM. 

c 




BENDING MOMENT DIAGRAM 

c, 




0C-£D-$'AE-$t' CFEDUa, 

parccbcla. with vertex, aZ£ 



TgBtant enxxisLered, <*t cn& 



SYSTEM OF L0ADIN6 



(18) 




SHEARING FORCE DIAGRAM. 

c 




OC-§wL BD-jwf.. 



BENDING MOMENT DIAGRAM 




A 






CD EH is a, K 

pcLrcubcloL with verier cdbE- 

OF -Hi. OOjwUAE^wtOA-AF 



^0 = 'vv = IT 



Shearing force at any point = qr- \l - - •'' ) 
Bending moment : 



Mo - M» - " T , 



,/■/-' 



Equation to elastic line : 

^ = ,»4ElV'' W )" 
I leflection at centre = „ ^ ^ 

Points of inflection : 

oF -.2111 ; <> ,; =.789/. 



I'd = ^ 1 






Shear at any point = g ( 5/ ~ Sx ) 
Bending moment : 

M> "(4^-5** + *°) 



Mn = 



1 



ic 



F 



M B = - M A = + jg 



1/;/ 



Equation to elastic line: 

">■- / , _ 5 /,. + 3/ i 
y ~~ 4SEI V ' 



,rl- 



Deflection at centre = vyl ^j 



W/ : 



Maximum deflection - 0.0054 £l 



where ' = 0.(1127/ 



Point of inflection : OD - 4 • 







I 






292 



FORMULA AND DIAGRAMS FOR THE ( ALCTLATloN OF BEAMS. 






U 












I = Span. W = T"t,il Load. . w = Load per Foot. 

Mo, M s . M„ Bending Moments at < ». a. B. R , \l k . I,', Reactions al 0, A. B. 

E = Modulus of Elasticity. I = Moment nf Inertia. 

Expressions involving I apply only to beams bavins i constant Moment of [nertia. 



@B 



e&jrv eszccLS tested' ai, both 



SySTEM OF LOADING 

M M B 



SHEARING FORCE DIAGRAM 

c 




OC-Ro BF-R. 



B 



-. 



0G-¥g>Ul-u.) AKrff^' 



BENDING MOMENT DIAGRAM 

O FUDA K G 




OG/Lia a parezicUt with axis CH 

pcirtl cfzero shear trig force 
00''M..BB-M t OBBvbaselut* 



(19) 



Note. -In these formulae, 

m - •> 2 ., I ~ 'II . n = 3a- - Sal + fir 

p = y/dn? - Slht 



Ro =; 2J (m) 

Mo - " T^(fl) 



wa 



R„ -«(«-•) 



\-2l- 






ma 



M| = T27^ ,,; " " l5al + s/ "' 

Bending moment : 
(i) .'■ i_ a 

M- — j|g [-6/ ■-- + 6*B(m) - a s /(n)l 
(ii) c - •/ 

' = "T2^|_ <* " 2/) " :; "' + S/ J 

at point where v = <>I> = l " 

"" 
Equations bo elastic line : 

(i) x <« 
V = 24 EI/ 



:,[/•<-' - 2aa(w) + o s /(w)1 



y = 2iEi^ r ' ' ' 4 ' ~ - n ) ' lr2 ( Sl ~ 3 "> + * < 4 r - *' '] 
lMl, """" :it A = 2l^r[ a2 ( 7 ^- 2a ) + ^(^- 8a )] 

Maximum deflection : when it occurs for 
(i) »<a 

at point where e = " < 3 '" " ^ 

4/3 

di) x>a 

648EI(2*-a)3 L M '"' " ! U a/ ' + L> 7 ' > 7 " "G 



= 



• it j mint where ./• = 



2 72 



or = 



3(2?- a) 
occurs foraj = a when a = .423 Z 

Points of inflection ■ 



u* 



FORMULAS AND DIAGRAMS FOR THE CALCULATION OF BEAMS 



293 



»«M f 



• 












I = Span. W = Total Loiul. w = Load per Foot. 

ai -vt \f« Bending Momenta at 0, A, B. 1!,„ K AJ K„ Reactions at o, A, B. 

]•; = Modulus of Elasticity. I = Moment of Inertia. 

Expieasions involving 1 apply only to beams having a constant Moment of Inertia. 



ff&eam.:enjcast*rcxLj*A< cne 
^ nr J ■ rmtra l LoclA- 



SYSTEM* OF LOADING 




SHEARING FORCE DIAGRA M 

c 







0C4W BD4W 



X D 



BENOINB MOMENT DIAGRAM 

o- - A * 



OC-rsWl 
AE&WL 



O - p; " 

Bending moment : 



Bb = A w 



(i)*<ij M.-5(ll«.-8l) 

M - - A WZ . M B = 
M A = + fa \\7 

Equations to elastic line : 
/ 



(i) * ^ o 



W, 



y SM5EP / 



(ii)*^| 



^ 



y = 



96 EI 



L(5a* - 15 /a 9 + IS As - 2/ ; ) 



7 W/ 
Deflection at centre = „^ 

Maximum deflection = 0.0093 



•/:; 



EI' 



where ;>* = 0.553 / 
Point of inflection: 01) = A '■ 












\l 






*[* ' 









& 



i 






A 






294 



FORMULA AND DIAGRAMS FOR THE CALCULATION <»F BEAMS, 



/ = Span. W = Total Load. w = Load pci Foot. 

M,„ M" A , M B Rending Moments at ' ». A. B. It,,, R A , 1!„ Reactions ii 0, A. B. 

E = Modulus of Elasticity. I = Moment of [nertia. 

Expressions involving I apply only to beams having a constant Moim-nt of Inertia. 

_ Wb (3 a 2 + 6 ab + 26*) 

2 (a + by 
\W(2a + 36) 



fiffiram, encastered, at. one end 
Icclc/ at any point 



SVSTEM OF LOADING. 
Mr, W 




(21) 



Ro 



SHEARING FORCE DIAGRAM. 

Ct 




R„ = 



M 



M A = 



2 «/ + /') 3 
Wa6(a + 2&) 

i' (a + 6) 2 
Wa*6(2a + 36) 



M. = 



Bending moment ; 

(i) «<a 

V\7, 



2 (a + 6)8 



rif\ Wb(sa'+eaI>.2bV Rn Wa i [2a>jb 






r = ., {a + ' /)y , [*(3* a + 6a6 + 26») - «<a* + 3a6 + 26*)] 



^/^ 



BEHDING MOMENT DIAGRAM 

C 




oc- w * b («;* b i 

2 1 arty 
AF w <*'6Ua,+3b J 



M. = 



(ii) .<• > " 
W 



[■>■('■'■ + 3a6 a 8) *(fts _ 2a 2 6 - a»)l 



2 (a + 6) 
Equations to elastic line : 

(i) •'• ^ " 

W/ "' J r i 

y = 12(g + 6) 3 El L~ ' ,,|:; " J + Ga/ ' + 2fia ) + :; '"" + ;; " / ' + 26*) 
(ii) •'• > a 

y = 12"( a +"/, rE I [{^- 3 ^( a + 6 )}{2a4-36}+(6*-2a)(a+i 

Deflection at A = I ;; a + i i, \ 

12 (a + 6) 3 EI\ + *°) 



Maximum defiV«-tion = 



Wa b 



i 



OKI \ 
at point where a = (a + 6) -J 1 - 



2 a + 3 6 



V: 



2 a + 3 

rj ,„..v occiii. at .'• = " when /> = .707a 

Point of inflection : (.1) - *(*+ ;i " / ' 4 - Q 

3 a- + 6 a6 + 2 5 



! 










%3 



J 

'4: 






X 










Kmn * *» nuoun kor THE p „ 

M« M, M. Bending Momante at [ ' oWI ^' „ _ 

'• = ***■ of Elasticity. . '•'■.. H.„ K„ K,, cli „ , |t , * 

Equations to elastic ],"„,. • " " = ~ Wb 

0) •'• < a 



SYSTEM Or LOADING. 



K = - 



Wbx 



- a, 

SHEhring FORCC OIA GRAM 



" 




OCtw BD-W 

BENOIN6 MOMENT O/AGRAm' 



AE-Wb 




SYSTEM Qfr LOAD)NG 




****^™~^ro7A~G~Rl^. 
J) 



B 






Or 



y = 



(ii) ./-> a 



6 Ela 

w 



!-(*--■) 



Maximum negative deflection 



' 7 ~ 6KI L (a ""•'■ ) ' ; + 3/ '-'-- *«&* + a %~\ 

Deflection at B = U7/! ( a , k \ 

3 EI l° + *J 



- -06+^y/ f :w],e W ..awr* 



//• 



Bending moment: 



**-£(•+*/ 






M, = 



2 



Equations to elastic line : 
(i) X < a 

"' r 

(ii) sc > a 

" r 

* = 24EIL''' ~ **( fl + ») + -' (»*■ + a > (« + ft/ - «*(»)] 

where n = (5 a- + 12 ab + 8 b*) 
Deflection at B = J^- ( 'jy + 4 a fr' - a*) 

Maximum negative deflection : it occurs at x in 

iaa* - 6 ,-(,,- - b-) - a?(2& _ „•, = 

W is obtained by subatitufeing this value of sin equation (i) 

for y. 






v 












296 



FOKMILJ-: AND DIAGRAMS FOB THE CALCULATION OF BEAMS. 



W 



& 



I = Span. W = Total Load. w = Load per Foot. 

>I m M A , M l; Bending Moments al < », A, B. K,„ K A , K„ Reactions at < >. A, I; 

E = Modulus of Elasticity. 1 = Moment of Inertia. 

Expressions involving 1 apply only to beams having a constant Moment of Inertia. 

:i I, 



Beajn, ervcas teretC olC one- *■/*</ A 
'$) projecting over a, support loou£ 



SYSTEM OF LOADING 





LjsT^B 




OC*j£w.BD-W 



BENDING MOMENT DIAGRAM 

E 




OC-JP AE-Wb 



Bendine in<>iin-iit : 



(i) ./• < a 

(ii) ./• > a 



K„ = - W - 



•0 



L'" 



SI, = W(x - a - h) 



" 



2 



M . = - Wfl 



M B = 



Equations to elastic line : 

(i) x < a 

//= Tk!^ \ x - a ) 

(ii) '• ^ " 

W r -i 

y = yrfi\_- ( " ~ x ) + Sba? ~ ,J " /,r + 3 " J/ 'J 

iVflwtii.n at II = — — ( 3a + 4A ) 
.Maximum negative •lt-ili-ction : = - 



27 EI 



where .*• = - a 



'I 



Point of inflection : <)I) = _ 



*,* 



M 



roMDM « DUaRAM « » -U,- LATON OK BBAMS 



/ - Span. 



29 



i 



W = Total Load. 



Mo, M,. M„ Bending Momenta at O \ I; <<; = ^oad pei Fool 

K = Modulus of Elasticity _ '"' •*» ,l ' ! Reactionsat 0, A, I: 

!!rr^'*'* 1 " 1 -* o^ssiSSL,,, 



?_tcovn eruxLsUrcxi clL one. end, 4 
projecting over cl support load, 

5r5rCAf 0/r LOADING. 

A 




when b>9l3cL RituAscitmrwards 
whmb<9J3 a, Reacts upwards 



SHEARING FORCE DIAGRAM 




Ro= 8 -(5«»-6i.) 

Uemling moment : 
(i) ■<• -S a 

* = " KI 4 ** + < 6 * 8 - 5a«) * - 2ao* + </j 
pi) .'• > a J 



0CR o AD*„b DE-R A 

BENOlNB MOMENT DIAGRAM 

E 



M x = _ - „./,' 




#£ *sa,paraho[a n>UA vertex alB 



y = 



Equations to elastic line: 
(i) x < a 

Wm - Q [2 ax* + (<>lr - f>a*)x- 6 «6> + 3 ,r] 
(ii) a: > a J 

g [2^- 8,-> + 6) + ]2 ,, (r , + ^_ 3aa;(w) + a2(n) j 

where n = (3a? + 8a/> + 66 s8 ) 
Deflection at 15 = -J^_ (,;/,= + ,;„//-■ _ „-.) 

Point .,f inflection : 



0D = 



5 a? 6 lr + \/ 9g* - 28 "-//-' + 36 ft 




» *^ 





298 



FORMULA AND DIAGRAMS FOR THE CALCULATION OP BEAMS. 



W 






c 



c 






/ = Span. W - Total Load, w = Load per Foot. 

M.„ M AJ M B Bending Moments al 0, A. ];. R , R AJ ]; 1: Reactions al 0, A, B. 

E = Modulus of Elasticity. I = Moment of [nertia 

Expressions involving I apply only to beams having a constant Moment of [nertia. 



fifrPtam projecting Over bctJLsupporU | 0Q ) 



system OF LOADING. 



r^s^cZ , , XT'? 8 
R. R* 



SHEA RING FORCE DIA GRA M. 



C 



]) 





('DUE \V 



BENDING MOMENT DIAGRAM 

J) K 

— — 





CO A B 

ODAE-Wou 



~t£uiu projecting over both 

Su^»pcrt> **lLA a load «/ 4»ach.**/tcL 
|A or\e bet*** turn Ouuupportt usisyrwim^t rxl j:%sfrm 




SYSTEM OF LOADING 



% 



J 



n: 



o 



K 



Wc 



n 



I 



Ho H B 



C 



SHEARING fORCE DIAGRAM 








// If 


I) 




JA 


F 


JC^^^ — /- 



DEW B J-'G-R MK\V t LM R 



BENDING MOMENT DIAGRAM. 

E 

G 




OE\V,a,.AF*M 9 i-W a U+to 
BGW c c 



Shearing force between and I ! = — \V 
Shearing force between 1 1 and A zero 

Mo = M A = - Wa 

Equations to elastic line : 
> - a 

Deflection al centre = - 



- Kl 



I Reflection at C or I! = 



6 EI 



■In 4- :;/ 



(27) 



Ro = i [W v (a + b) +W A |- W cC j 



I, 



K = ' {w c (o + c) + w a ^.- \v„,; 

I ►ending moment : 



(i) x^o and > (-a) 
in) .'• > <> and 5 

Mo = - \\\,a~ 
M 



M, = - \V„,„ + ,•, 

M, = !: t W 9 [a + s) 
M„ = - W, c 



A "" 



= j(W A 6 - 2 W, , - 2W D «) 

Equations fco elastic line : 

(i) <<o ami =^(-a) 

y ~ 48EI ! SW '"'' : + -'1W I1 ^+ (m)oa:] 
(ii) •'• =^ o and < r 

V = 48EI \(- W a0 + 2W c c 2W D *)^ + 24W D oa (»)**) 

where m = (3W A 6 - 8W ( c - 16 W & a) 
Deflections al A. ( ! and D: 

,,',.-, ( W A i - 3W c c- 3W D a) 



3 A = 



|s ' K1 ]i«;w ( C (b + c) + 8W D ai - 3 w ; ] 



d ]S " KI |l6W D o(a + />) + 8W, 6c - 3AV 6 












K "" m '" K AN " DUGRAMS ro * - -— , 0, „,„,., 



7 = S| ""' W = Total I - 

M„. M v . M ls Bending Momenta at I », .\, B. '' '"" ' , Load per Foot. 

E = Modulus of Elasticity. K '" B * K « Reactions at \ B 
Expressions involving I apply Dnlytobeamal • Momenfc of Inertia. 
y ^ beams ^ving a constant Moment of Inertia. 



299 



tLnsynun*ls'uuz/, system. 



Utses-tbtLLecL tea**. \ 



SfSTEM OF LOADING. 



(28) 



*»- Tb ,' "'■ " (a + 26)+ „, /,-■ _ Wc c * I 



-a -£~ ~~£ — ^ c ..^ 
R R A 



' 



26 h c ( fl + 26)+ M *_ „,„,! 



SHEARING FORCE DIAGRAM 

E G 




OD w a a AG c w c c 



Lending momlnt diagram 

E 





K, = -±- / 
Bending moment : 

Oi) '• > o and < 6 ai p ' , 

/ 

M A « - 'If. 

■> 



M a = - '!±" : 






Equations to elastic line: 

(i) •'• < o and > - a. 

('■') '• > o and < 6 

»-l,e le »,^(- 4,,,,- A + „,//_ ,,,,/,,,, ' 

Deflection* at 5 , BandC: 

— 

+ 46) - io A y + i',r..„^J 
'w> a*(3a +46) - 14 p + 2 m,, 6c 8 ). 







300 



imumil.k AND DIAGRAMS FOR THE CALCULATION OF BEAMS. 






lV« 



& 









r<3r < 




/ = Span. W - Total Load. w = Load pet Foot. 

M c , Mai M b Bending Moments ai l ». A, B. K*,, R* Rb Reactions at 0, A. II. 

E = Modulus <>l Elasticity, T = Moment <»f [nertia. 

Expressions involving I apply only t<> beams having •< constant Moment "!' [nertia, 

Ro - Ivv = 7 } { ' 2w * + *>il ) 
Bendins moment : 



€£uri projecting over both, supports, 
d^tribitlexL b>acLs over hang >tsig '0hed , f)Q\ 



SYSTEM OF LOADING. 



r w/> O w //> A w/> £ 




SHEARING FORCE DIAGRAM 

G 




ODAG wa 

DE FG Ii R A 



BENDtNG MOMENT DIAGRAM 

D G E 




01) AE *p*.FG$? 

CIJ& BE ewe etpuu para Lolas 
wilh vertices at C & 7i DEE is a, 
Xparohctou for uniform load, on.DE 






'mjfirw prfj>4Cti^ 9 -^ >r both supports 
^waKunjJprrrvLocujLaLL over 



syrrm*ts-t* uzl, Sy ji/^jrr, 



SrSTEM Or LOADING 



C 



wper ft j\ 



*t& 




SHEAR/NG FORCE DIAGRAM 

E 



c<£ 




ODAG wam-GF-fy^i) 

BENDING MOMENT DIAGRAM 

F G 



B 

rhG Lsa, 




OFAG n ; c 
CF^BG 



(ii .'• < o and ^ - " 
(ii ) .'• > o and ^ / 



M, = - | w t lx - wcA 



M„ M A 



ir.r 



2 



Equal ions l" elastic line: 

(i) x < o and > - a 

'■' = ->TY\ ! "' ( '''* + 4 "'' + G "' J •''"') + { "'i r ,; "'" *)*! 

(ii) x ^ o and ; > 

y Yi y\ I"''"'' _ - r ' "' + r '"" J '-' J + <"• P - 6 to* J) s] 

Deflections at - . B and C : 






384 KI 



•"•/'•/-• 24 w»»J 



",. - ", 



= 2m {■'"' ( " :i + 2 " v/ ' 



/,-,/ ' 



• 



(3(») 



Beinliii^ moment : 



(i) 'So and > — a 
(ii) -■ > o and / 



•' 



M„ M. 



?/Yf " 



2 
Equations to elastic line : 



M. -£(!■- 4rf) 



(i) .'• <j a and > - // 

(ii) ■'• > o and -^ I 
V .,," 1< rj |.>- 4 - '21, + 6oV + (P - 6a s Qa;] 

DcHccti.-ns at - 15 and C: 

irl 1 i v 

°« = °c- = §4Ef ( 3 "' + G " J/ - I 1 } 






%l 



u 







M* 















Continuous Girders. 

CONTIGUOUS girders are not now generally employed except for swing bridges. 
This is chiefly owing to the effect that any change in the level of the supports 

of the birder may have on the calculated stresses, it is not necessary that the 

supports should be on a horizontal line, but they must he at such levels as will 
ensure the reactions being as required by th.--.ry. In practice this can '"■ obtained 
by actually weighing the girders at each of their bearings and adjusting the levels 

until the COrred reactions result. This method was adopted for the viaduct approach 

spans to the Forth Bridge. In calculating the stresses in .■..ntime.ns girders it is 
usual to assume that the moment of inertia of the girder is constant. This assumption 
ia rarely correct* but the error caused by it is not of great importance, especially as 
the ordinary formulas give somewhat higher stresses than those that would be obtained 

had a variable moment of inertia 1 o considered. The effect of a diffidence of 

temperature on the various members of a girder may affect the stresses considerably. 
This dors not admit of theoretical investigation of much value, hut it indicates that 
great refinement in calculations of this kind are unnecessary. Ir would appear fro,,, 
the investigations of M. Levyi that a difference in temperature of 25 deg. Fahr. 
between the flanges of a continuous girder may increase the stress- by nearly 2 tons 
F e, square inch, and this, in his opinion, makes it preferable to use independent 
Bpans in place of continuous ones, where appreciable diile.vnces of temperature between 
the upper and lower members of -inters .-an occur. 

It should also he remembered that riveted joints, defective detail, and many 
other matters may cause the actual stresses in a girder of any type to differ verj 

considerably from' .1 bteined by calculation, as show* by experiments on a large 

bridgi over the Loire at Cosne. 2 

The bending momenta and reaction* ... a . Unoona girder, of an, number d 

,,,„,- , [orfed with concent* I or dietributed loads, can be obtamed bj the 

theorem of three moments, *hich is as follows:— 



i *« 



- Le Geoie Civil," September 28th, 1896- 

■ » Annate* des fonts et ChanaieeV' November, 18J<>. 



\e 



f\ 







"•' 



is 






& 



< 









1 






302 



nUi.MlLJ; AND DIAGRAMS FOB THE CALCULATION (>F BEAMS. 



Let I, f- l 3 etc. 

/r, ,/:, w a 
W, \V.~W 

Mo M A U B M, 

So ,S v Sb |S i 

h h k /< l: //, 



The Three-Moment Theorem. 

consecutive spans of a continuous girder 

distributed loads per anil of length on the**' span 

concentrated loads on these spans. 

bending moments at supports < >, A. B and C 

shearing force at supports 0, A, U. I ! 

vertical movement oi supports I K A. B, C. 



Case Co). — Loads Umforirdy Distributt <l 



M 



<> 







n , 



T 



06 vi 






Bl 

B 



ii 



M 



*'. 



j 



&, 

So 



_,;... * 2 



inmiHiiiiimiiit! - nt . turn mmuuiiiHnu: 



c 
C 



*j 



I — 



Then M,,/, t2M A (/ 1+ LJ + \| l; /,= - i (,•/,+ ^) + 6E1 f- B *' - ^ i°] 

'l 

Similarly M v /, + 2M,ft + /,) + M, l A = - \ {w I. - w /. | • 6E1 '/'' ~ 7 ' ,! - , ' B " * J ' 



i ' 



Thus . ;11|V aumhei of equations maj be obtained connecting am two consecutive spans, and the 
required moments found 1>\ elimination, since the end moments are zero. 

Case (b). — Loads Concentrated. 



k—nlt J 



(SO I 




w, 



--71/ 



*; 










+ 6 El |^JlA* _ *a - *o j 

Simrlarly obtain anj number of equations. See Note, Case (a). 
11- last tmn ,„ all tfie above equations refers onlj to the effect of a vertical movement 
01 the points oi support, and ran generally be ivJK-t.-«l.» 

Shearing Force The shearing force at anj section nun be obtained fchus:~ 
^•t -m k = bending moment at any section 

> K = shear at the section 



... M k+x = bending momenl at any other section 
\\ and w = mtervening .■xicn.al forces 



M K+ x 



w r 



Then M K + 1 = M K + S K a - \Y y - "' 



1 




i*-> 



ThatisS K = a; (M K+ ,- M K + Wy + ^ 
jn the ;;x«'"i.l- which folio* the above equations have been applied, and it is assumed 



that ao vertical movemenl occurs at the suppoi 



cation, Bee ' >!• '(''nVl-VaMMM 1 ' sli' ^i^. ' ,IV ''? , -'; , V 11 " f V 16 theorem of three moments, and it* pi ''I'l' 1 '' 

luits, l,y .I«,l,„son. Uryan. un.l TunieauW (Wiley and Sons, New fork). 









" " " — - • -— ... . _. 



'. *,, /,. / = Spans. W. W u W W n o 

"^•a*" ;;<^;r ,nM ' j »■ : >*-i b] Foot 

IS = Modulus of Elasticity. *" ■*' K « K^'tions .to v B 

All Bzpreasions involve I. and therefore apply only to I i = } SobmA ° f Inart * ' 

^ Ur^us Girder over t^T^U^^Tl ^ ""^ 8 '^^^ H*""" "'" '<-'- 

UTuSorrrt load >v ^// „„„,. r " /J) 

K - - R„ = J w 



.303 



i*.««««/uo <j ira*r over- t*vo , 
uniform load w cell over 
SYSTEM Or LOADING 




SHEARING FORCE DIAGRAM 

E 




9£^oAE-AB z §^BFR B 

^ 57 ^^Nr~DjAGR A hr 



E 
DE-ACEG-^' 




B 



ertuxs aLE & G Oh Bit V ^ <? o^e W 



Points of Oil el BK 




"0,1* vr-aer over hvo tmjuiual 
JgjW/ s^v, on. L r & w , o rL / T 
system ofloaoJng 




~sh1ar, ng force diagram 

E 







ff 7 ^ m ^^MENT-b~^GR^i 

1 lfo>^ yliisi l^'^artlr 






a', 



°(3fo-4a*) 



Bending moment; * < / 

//• 

8 

^o - M B = 

Equation to elastic line : .,•< J 

f, " ,, " , ' t "" 1 at centres of spans = " V ' 

192 El 

Maximum deflection = 0054-' 7 ' 

EI" 
where * = 0.421 1 

Points of inflection occur at Hand K, where 

OH = BK = 3/ 



(2) 



1 / '"> I* _ "'. A ; + U\, I 






''\ - tot + t/U.) - (U n + Rj 



B 4* 2 " iift + y 
Bending moment : a; < /, 

m, = R ,• - "";■;" 

M = M a = o 



8 </, + g 



Equation to elastic line : .<■ < /, 

V - 24EJ |" v '" 4 - " : "' + ^(4R - ^/ 
Maximum deflection on span /, is found from 

4<v- : - ia ]-!„.<-+ n;„/r - ,r,/, = o 

Points of inflection occui at II and K, where 

2 R ■> M 

OB = -"a.-l UK =— b . 









w 



& 



t c 



r<sr < 



304 



FORMULAE AND DIAGRAMS For THE CALCULATION OF BEAMS. 



I, li, 1^ h = Spans. Wj V7i, W fi1 W a = Concentrated Loads. w t n\. "■, »,- = Load ei Foot 

M , M A , M B Bending Moments al < ', A, B. I»\„ R u I,' 1; Reactions al < », A, B. 

E = Modulus of Elasticity. I = Moment of Inertia. 

All expressions involve I, and therefore apply onlj to beams having .1 constant Moment of Inertia 

" (3) 



'3)ConS'SLU£)us ylrcter wer triree usieqructZ spostS 
usuJcrrrt toaxls n/, en L .w, on I, &. >v, en Lj 



SYSTEM OF LOADING 



B 



= 



W. 



w * 



Wj 



R R A R g R c 



SHEARING FORCE DIAGRAM 




0D-R c EF-R, 

GHR B KC-Rc.AER a ».l, BJI R c w,l s 



BENDING MOMENT DIAGRAM 

F N A Vll VHWL C 




G 1) K 
fG w ^HK w 'J' LM g£ OGA.AKB 

fiMC otr-e par-ctbobxs with vertices <ztG,K&M 

P.Q.R (S F (hxujnajn) are mutdle poutts of ON- WW C 

wm "* 



(4) ContLnuvujgirdes- ever two eqiuxl spans 

— Uo W'"£ & oerdtraL concentrated Lfiniij; 

SYSTEM OF LOADING 



O 



f 

Ro 



w 

U 



r 



B 



R 



t> 



R 



SHEARING FORCE DIAGRAM 

G 




OE-BJ I 4W RF JiG-Uw 



BENDING MOMENT DIAGRAM 

4JSLB K c 




1) 



E p 

AFCF'f BG # 



_ 



H.-*/"^ 



1 



U 2 + M *j 



M, M 



/ 



M B 



M, 



/ 



M A 

R "' L. "" 7 M| 

M„ M, = 



M, 



M , 



- I w I -4 M .L 



8(/ a + y 

Points of in ll' -'-1 ton ; 

•' I! 
OK = — ° 



c\v 



•'I.' 



M.< 



(!) 



i;,: v w 

Bending moment : 

M x = £(8f-ll*) 



2 

/ 



(ii) ■'■> - and < / 



16 



M„ =M„ (. 

_ . Mb = - A W/ 

liquations to elastic line : 

(i) x ^i 



y 



= !n;|^( 3 ^- V "0 



/ 



(ii) •'• > -.iii.l - / 



y 



= 96El MIV-LM/..^ !.-,/>-, 

Maximum deflection : .»• < 

2 

= • IM , ' , -> iii 1 mini w here x = AH I 

r* 1 



Deflection at I ' = 



7 \\ 



r'6S II 

Points of inflection occur at II and K. 
where OH = DK = ,", I. 



" 



: 






*v 



lAJfc 



^M 






*. 



M 






• 





















* 



FORMCL.K AND DIAGRAMS FOR THE CALCULATION OF BEAMS. 



305 



, / / / _ Snans. W. W,, W.,, AV. = Concentrated Loads. w f uk. ?<\, w z = Loads per Foot. 

M My. M B Bending Moments at O, A, B. K u , i; v , II,, Reactions at 0, A, 15. 

E = Modulus of Elasticity. I = Moment of Inertia. 

. ■,.«.!•.-,* T ami t1ii*vt»fi wi'ik niiiilv niilv t.i Iik'iiik lrivimr •» r»im«tf»nf Minni'iit (if Tiwrti-.i 



Vll expressions involve I* and therefore apply only to beams having a constant Moment of Inertia. 

k <» - — y- 

K B . W, + W fl - (Bo + i;„) 



'AiuxuL 



(5) 



^/Sr£M QF LOADING 



In 






R 



R 



M„ + W,,(/ s - 4) 

I'D — I 

M = M D = 



SHEA KING FORCE DIAGRAM 

G „ 







M„ = - 



W.^-tfJ + W.^tf-d.") 



2(/, +/,» 
Points of inflection occur at H ami K, 



OE-R.Mlt.BF'VTfKBGW-R, 



BENDING MOMENT DIAGRAM 

ABB K C 



where ' 'II = 



and DK = 



W, - K„ 
W 8 rf 9 

W, - 1J„ 



/^ 




J? - - F 

Ag Wd/Crd, ! CF W t cL f (l*-d.J Bn Mt 



xtL spans 



(g\ Ccntuiiwiis girder over three. unequal, spans 
ccncenlraled, LocutsW,tm I, Y^on li&Wj on t 3 



SYSTEM OF LOADING 

w, 



(6) 




^d^Mj 



\, i, ... .4 Z 4 ^ 4 



H, 



n 



H R F 






Rh = 



W] ft _ rfl ) + M B w + Wgjj^ - *» + M„ 



'. 



R,,= 



w.^ + ijg + Ws + ?■* + *■ " =s 



SHEARING FORCE DIAGRAM 




\X.J, -f M„ 



3**3 



R F = ^ 



M = M F = I ' 



*, 



(4 + 0(* , - tf )-"7 J ( 4 "*) 



OC /4 J57/ W,R ,BKR B W l tR . 
J>L-R B W,+R„DM-W J -I'r FNR r 



BENDING MOMENT DIAGRAM 



AP 



B C DQEF 




M„ - 



M K 
BLM e .DM-M' 



M„ 



— — 417T+ SkS + W - ** a 

W I ,, j.X + ^»(2// - 37,^ + *■) + M B ^ 



■2(1, + ' i) 



RR 



►*V 




^•. 









lV« 



& 



( 






A* 



( :iOG ) 

Special Cases. 



Inclined Cantilevers and Beams. 

Note. See also Conventions "n page 281. 

1 = Span. W = Total Load. w = Load per Foot Horizontal 

M 0l M v . M B , M,. Bending Moments at < ». A. ]:. Section Distant x from 0. 

E = Modulus of Elasticity. R 0J R v R B , Reactions at I '. A. B. 

d At 3„, Deflection al A. B. I - Moment of Inertia. A, = Area of Cross Section. 

Z = Modulus of Section = -. (y, = Distance of Extreme Fibre from Neutral Axis) 

!l\ 

j\ = Direct Stress due to External Load. 

/, ~ Direct Stress due to Bending = ± ^ ( + for Compression Pibrc 

I for I ension Fibre 

./,'„.... = Maximum Direct Stress =/ ± Max. Value of /# 
Expressions involving I applj only to beams having a const .-mt Mni,,m „f foertia. 

a i< in I U . when sin u or Tan a 

All Deflections, y oi 8, are measured from a Horizontal Line through the Origin 0. 

Note. -The Bending Moment and Shearing Force Diagrams for the following ,. milai in each 

case to the corresponding case with supports on the same levels. Where there is a parabola it will be 

oblique, rhe simplest way to draw it is first to construe! a parabola in the ordinary way on the 

actu »l length of the beam OA or OB. Al anj section transfer the ordinate length asured at right 

Jesto the beam to a vertical ordinate. The oblique parabola will be obtained In drawing through 
such points : see, for example, parabola I >HA. ( !ase 9. 



(1) ( 'anttien r at Angle « to Horizontal. Concentrated Load W at any point. 

R„ = W 
Bending moment ; 

•'' "- a . M, = W (,■ a) 

__ '• ' " • -M, = () . Mo= - Wo. 

Equations to elastic line i 

(i > '' ^ " • !/ = ( . j.j [ - .i- + 3 aa/j + x i. in a 
(ii) ..• > a . y = - _ [ - ft s + 3„->J + ,. fen a 




<5«? diagram* (xuse Q) Pajpe2$2 



*A = 



+ a tan a 






Stress : .'■ < " 
W sin a 



3 El 

Wa 2 a 

"'■■ 6Ef( 2a + 36) + /tana. 



A, 



,/-•- ± t.. •- a) 



( -in a •' \ 

A«. = ^ ( - ± I •'! 0. 



(AlLCaSBS -> N <™ -$ [The deformed elastic luxe is in all cases shown dotted. 

P f" for a wom ^ section at horizontal distance x. 

0") ^lu-.l - V.T.,] V„lu,. of/Bu ^ ^..^ j^^ fche ;il(M for abso]ute 

maximum Btress. 
("0 ^ ■'II measurements are here taken horizontally, and rcis a horizontal 
intensity, the expressions are similar to those already riven for supports 
"» same level (jk^-s -| ;{,„,,. 



s 






e ams. 












«,= -'« 



/»' 



4 



i* 



m 



mmttLM ^ WAGRAMS « ^ E C,,,,-, V ,, ()X 



N ' OF BEAMS. 



2) Cantilever at Angle « to fforizanJn} u ■ • . 

Ifo A *"*•!■& M**** L I to per Footff i , 

Ro = /r/ 

10 



307 




Bending moment: 



•'• < / 



S&ftoW*™* Case <g> Page 282 



Equation to elastic line; 



M = _ !* 



« < / 



^ ~ 2T El (* ~ *^ + 6^ +aJ tan« 



Stress : 



wl 4 

8EI + * tan ft 



sin « 



,; -..(«. . , - 



A-±&(.-iy 



f - ml i 8IM r/ 7 \ 



(3) te. ^3, .„ 7V „,,„,/„, IWrw|| ^ 6W , o , // . (;/(7y: ^ fMv 




R = 

Bending moment: 
(i) x < a 



7 



M, = 



See diagrams Cause5 PcLge284- 



EL = 



\\7,,- 

/ 

Wa 






AM4£; 






M, = 



Equations to clastic line : 



/ " 



'" : " • '-mil-** (• + «)] + ? 

(H) * " ° " y = 6E1 / [ ~ W + * ('• - «) : ' + «** (« + 26)] + ^ 

■ vi,,,, 1 it ..• / 



MnXillirilll .IrlllThull ; 

(i) a > b 



M occuia at x m ^" ( a + 2 b) + — 



To get o,„„ insert x in equation (i) fory. 
No turning point in curve between 1 1 and B when : 

3 Wba 



2 Klji 
Wb 



(i) a>5 

(ii) a < 6 



A > — 

2EJ (a + 26) 

h < —=- [b-aj 



3EJ 



" r 



S| io ss , 



" Mll v will occur at A when It = -— - la - b j. 



(i) 
(ii) 



./• < „ .• __ - K M sin a WA./- . WJ r - sin a 

• y* = ± 



' > a . /; = 



A, 

1«, : sin a 



c . \w> r — sin a an 

(Z~ ' - ; = I L A, * ZJ afcA 

W« / \ War + sin a /-an 

^- ± 7l( | -*J • J * = l L £ ±^Jatpo.ntl 














» 



' 



w 



& 



t c 



r<ar < 









::i)s 



FORMULA AND DIAGRAMS FOR THE CALCULATION ok BEAMS. 



SPECIAL CASES. 



Note.- See also Conventions on page 281 



/ = span. W = Total Load. //• = Load per Foot Horizontal. 

M (1 . M A , M B , M^ Bending Moments at 0, A, B, Section Distant x from < ». 

E = Modulus of Elasticity, L,„ K x . R B , Reactions at 0, A. B. 

3 A , fl B , hellection at A, B. I = Moment of Inertia. A 3 = Area of Cross Section. 

Z = Modulus of Section = . (//, = Distance of Extreme Fibre from Neutral Axis). 

. f\ 

J] = Direcl Stress due to External Load. 

, .. .... , , ., ,. My/ + fur Compression Fibre 

/.. = Direct Stress line to l.cnilim; ^ + — - ' ) 

I \ - for Tension Fibre )' 

J .'... = Maximum I >irect Stress = f\ ± Max. Value of /^ 
Expressions involving I apply only to beams having a constant Moment of Inertia. 

a is in Degrees when Sin a or Cos a. 
All Deflections, y or '<>, are measured from a Horizontal Line through the Origin 0. 

Note.— The Bending Moment and Shearing Force Diagrams for the following are similar in each 
case to the corresponding case with supports on the same levels. Where there is a parabola it will be 
oblique. The simplest way to draw it is first to construct a parabola in the ordinary waj on the 
actual length of the beam < >A or OB. At any section transfer the ordinate length measured at right 
angles to the beam to a vertical ordinate. The oblique parabola will be obtained by drawing tl„-„u»h 
such pomts : see, for example, parabola < >1IA. Case 9. 



( 1) Beam simply supported at Different I, wb. Uniformly Dutributed Load w per Font Horizontal 




Ses dcayranus Case® Page 



Total load W = wl 
Bending moment : 

1" 

t(*f~ 

Mmi. = g at centre. 

Equation to elastic line : 
m; r - kx 



I" 
R (l = R A = 



y= i'IEI L' W + ftf] + j. 
Point of maxirnuin deflection is at the value of x 



1 .'' ; - (J /.,-' + p + 



m 

24 EI h 



= 0. 



ft 'I 

There will be no turning point between and A unless the vain,- of x is + and : I 



Stress : 



^« n «. will just occur at A when h = 



wl* 
24 El 



./; = 



"' SID a 



v i 



"/sin u 



r(— i) 



■ /j = ± 2z( fa " ''") 



2A7 : 1 + at °i - at A) 



/,...x. = ± s/ at centi 



' 



i 



■»* 









-*• ti 









N>RMOX* AM. DIAGRAMS For T HF Pa, 

HE 0A **MK» OF BISAMS. 8M 

i ) Inch nod Brum, Pin Joint,,? a , R „,,,/ „„, • 

l(tal{) - Concentrated Zaad-W 




R„ = 



V„- 



^Va cos a 



V Wb sin a 

» o = 

h 

y ■ 









Stress : 
(i) ,■ < a 



./; = 



Ro cos a 



■• ."SEE 1 1 y^jjrv ■* 

to occur at A in.I n„ i-^ . lu ' lx,n 'um J 'efleetion 

Cum -b* eetn ^! , ; ,ht T f ° r »° ^g Point in 

U and I,, use the Equations of Case (.3). 



'in. ix. — 



A, 
'»,. cos % 



A = ± 






at 



'iii.t\. — 



K cos « W5 a 



mi) r > a 



at A. 



./; = 



y; 



in.. > 



a 'uuuc. 

!fe«l _*.«*« + \v rin . " * 

_ I',, cos a + Wsii, a Wad i» 

\ ± ,„ at A /• « «o«ob« +Wsin« 

A, 



at B. 









2>w*r»W W „, per Foot Horizontal lJor » d » 







T » ' 



//•/ 



,vlr 






74 



Stress ; 



Norn— For Bending Moment, Maximum Bending 

Moment, Equations to Elastic Line, Point of Maximum 

Deflection, Maximum Deflection, and Conditions for 

Maximum Deflection to occur at A, use the Equations 

of Case (*4). 



. K„ COS a 4- WX sin a 

I \ = — 

A, 



,- H lt cos « 

i at n. 



. _ R COS a + ,r/ sill a 
• nun , ilt .\, 

A, 



A ( Jl " cos a + 7> SU1 a ) ± -- at centre. 



I* 



lV 



X* 



& 






2 



J 



»8 



310 FORMTJLJS AND DIAGRAMS FOB THE CALCULATION OF BEAMS. 

SPECIAL CASES. 

\..n:. See also Conventions on page 281. 

' = Span. W = Total Load. w = Load per Fool Horizontal. 

Mo, M AJ M B , M,. BendiiiL: .Mmncnis at ( >, A, It. Section Distant a: from < >. 

E - Modulus of Elasticity. K„, K b i;,.. Reactions al 0, A, B. 

3 A , o l: . Deflection al A, B. I Moment of [nertia. A, = Area of Cross Section. 

Z = Modulus of Section : . (y, = Distance of Extreme Fibre from Neutral Axis.) 



/J = Direct Stress lue to External Load. 

/• i >;„ *. o< l i. i- "!,'/ , + for Compression Fibre 

r - Direct btress due to Bending = + -( ' 

I \ - for Tension Fibre 
./"„,,. = Maximum Direct Stress / ± Max. Value of f z . 
Expressions involving I apply only to beams having a constant Moment of Inertia. 

a is in Degrees when Sin a or Tan a. 
All Deflections, y or 3, are measured from a Horizontal Line through the « 'nun 0. 



(7) Inclined Beam, fixed at and simply supported at B. Concentrated Load W. 

d*° R = ,'hV,^ ;;„■/ + ,//] 

O w J 

l 




•«, 2 -^[w« 2 (2a + 36)1 



I lending moment : 
(ii .'• ■< a 

(il) x > n 



M. = M + U,,,- 

M !;,.(/ - c) 



M 



= 2^[W^(2« + 36)1. 



'■ tan -/ 



M„ = - J^[wa6(a + 2 6)] 
Equations to elastic line : 

0) *~ a ' !,= 6El[" l{ "'" " 8M W] +■ 
(li) '' = " • ^ = ,;ei[- R <^ - 3M„- + W(,-- „,] 

= <'»ElL~ ^"" " :i ^ I "| + " ta " a 
Point of maximum deflection occurs at 



+ ./• tan a 



■I 



Stress : 

(i) ■'■ < a 



x = '-" ± * j '" ~ *n( \Ya* + 2 EI tana) 
where m = ,M„ + Wa ) . * n = (W _ r o)i 



./; = 



Ro -in 
A, 



' - ± 



Mo + H,,' 



I c> a 



f = 1{ " H " « M , M 

■ "' ~^ ± 2 '" ;f ;it A '"' ' ' respectively. 

fi = - /.' = + " (/ ~ j ,• 1{ i sin a 

~ Z " • / »" X 

. Rjj sin a 

' — r — at II. 

A, 



A 



M 

± ./ at A. 









K " ,tM "" E A ™ DIAGRAMS m R THp -.„ 

Ml CALCCTUT.ON OP BBAHS. 



(8) /„.•//,„,/ Beam, Jived at O and *imml ' 3 

' *'»'/''// supported at B /' v , 

^aSSi **^ ****** ,„.,„., 



311 







I? 3 

,1 a = 5 ua. 





,;, '"ling moment: 



C~ < 7=H^» 

sSTdtapnans see Case @ Aue ^,9/. 



Mo = - 



8 



1 l2 8 ^iM point whereas = -i 

8 ' 



l2o r"'ui, 

Equation to elastic line ■ y = J_ , 

«*»— ^£: *°!: 12 * ? + - 



Point of inflection : I "'~ " b M "' + ,; El tan 

./■ = - 

Stress; / = ~ ° *"* tt + ""■' s 'n u 



-• R v sin r/ 

. a1 A 
A, 



BL 

2 ./ m ,v - — ± ^ at 



'u 



.' mu — i: M 



•it , n * 

' — m*j poa ,,L ■' = — = . 

: '> '■■■><>•>■' h. .M,„ a , w4 '" 8 

'" " D T" U " ** " " Fm "- • 

Bending moment: 




K - M + B x - 



SHEAR/NG FORCE 
0' A GRAM. 




M - wt! 

if 

12 



2 



AI A = _ 



wP 



I 



J»m»t. pos. = o at a = -. 
Equation to elastic line : 

Poinl of maximum deflection is at the value of .,• i„ 
wo 8 - 3V- 6M * + 6EItan« = n. 

Point of in/lection : 

x = 0.211/ or 0.789/ 

Stress : 






Mll.'lX. ~ 



. - K u silia 4- "'.''sin a 

y,= A, 

R 8ina M., 

- ± y "at (I. . ./;„,. = 



A, 



R A sin a .\f. 

± ./.<t \ 



A, 



'-« m^Z p H ahoUiA ^ 



R, / 



to 2 



a>ir 




i 



I 



^>ax 



r 



3 1 2 



FORMULA AND DIAGRAMS FOR THE CALCULATION OF BEAM-, 



iV« 



& 



<s 






SPECIAL CASES.— Refer to He*lin«, r on ].a^- 310. 

(10) Inclined Beam, fixed at h,,th ends. Concentrated Load W at any point 

M° SrSTEM OF LOADING 

W Mb 




\ < a. 



' 



Q SHEARING FORCE DIAGRAM. 

D 




R .. = ),[_ W6 B (3a + ft)] 
R B = ^[Wa 2 (a + 3 6)] 

M B = - '_.[ w " :/ '] 
M , = I [ 2 W-v, ] 



oc^t bfJ& K ^ tml 

due to fared ztuLa 



SENDING MOMENT DIAGRAM 

A 




00 



t Webb 



RB i = Wg^b =Shlfl ofx^&i^ alB 



due tv furify. 



r.rii'lniL' im.nm.-nt : 
(i) •' ^« • -M, = M + l;,,,- 
(ii) x>a . M, = Mo + \l„, W , ■■ a ) 

Equations to elastic line : 

(i) '• " " • y = ,; F1 [- K --' - ' " 3Mo^]+ ajtana 
<"> '^« • .V = 6 -gj[-U.,>-: , ..M 11 ..- : +W<^ a)^r 

** B 5TP + ««■" 



Point of maximum deflection : 

(i) »>b 



tana 



M ± v M,, +:.' R, EI tana 

./ _ — — -- -■ ■■■ - 



Ro 



Points of inHection : 
(i) x < a 

(ii) x > a 



(ii) a < 6 . .,• = 

Where m = (M + Wa) 

r// 



m + J 



± n ■«/- + nf\Y,/ + 2 EI tan a) 
n = (R - W). 



.c = 



3a + 6' 



g(a+26) 

a + 36 " 



Stress: (i) x < a 

A, * /• - ± j i 

at i » .»!• A respectively. 



./;= - 



_ _ R„ sin « fM<, M„ + K„^| 
•'• " ~ A, * \"Z ° r Z I 



/, = 



B B sin a 



(ii) ..■ > a 



A, 
respectively. 



js-±^2»(i-«) 



• 



R B sin a j M , M % 



in a i 31 , 31 . \ 

— ± {t-z ! ! 



at B or A 



4 



p^ 



4 I 



HOi 



Moving Loads. 



"•** 



w 



IB I 



: 



- 



ft 



R.-«- 



' z 









H* 



/ = Span. 



W, Wn Wj = Concentrated Loads. w = Loa<l per Foot 

,., -d i> I' Reactions at (>, B, C, D. S , s u> S x = Shearing Forces at 0, Band Section Distant a;. 

n,>« * l li* **CJ ■' 

M,. Mp, M» = Bending Moments at E, P and Section Distant x\ 
./• in all cases is measured from the left support towards the right. 



w 



SYSTEM OF LOADING. 



oQ 



4b b 



MAXIMUM SHEARING FORCE DIAGRAM 

c 




1*36 Si 



N 



(1) Single Concentrated Load U\ 

Shearing Force : 

Tin- greatest positive shearing force at any section occurs 

when the load is just to the right of the section, 

M:l\. pOS. Q x = 5 

The greatest negative shearing force occurs when the load 
is iust to the left of the section, 

Max. pos. Sx = - . 

.-. when a: « Max. S = Ro - w 
when ./■ a / Max. S B = - K„ = - W 

Bending Moment : 
The maximum bending moment at any section occurs when 

the load is over the section, 

\V.'- /. \ the eiiuatinii to a 
Max. M x = -y (/-<j ^y a 

\\7 
Absolute Max, M x - M B = — 

(2) Uniformly Distributed Load, w per foot run, oj length 

greater than tic span. 

mJS • 1 K, ~* .ecu* when the rig , 

is folly loaded up to that seetao... (J _ ^ ,,, ail ,,,,,„,,., ,,„ 

right j 



BD=W 



MAXIMUM BENDING MOMENT DIAGRAM 

O E ,B 




OE-EB 



QEfl i? a, parabola with vertex ObE 



SrSTEM OF LOADING 

wzzaf=± 



J2=£ ,fl 

i Jr* 

MAXIMUM SHEARING FORCE DIAGRAM 







Max. pos 



* " • , ' r ( 



fruiu 



So = 



u>z 



BCisaparabola with verteocatll 
OD.. , , - .0 



D 



MAXIMUM BENDING MOMENT DIAGRAM. 

E 




Max. neg.>hear when the l,ft«.nly is fully l.,ule,l. 

w ar 

Max. neg. S x = - K u = -77* 

w I 

,;r:^t^:: ^d,,, >,,,,,, ^.y^. ■ 

i;„ - Rb = "o" 



M 



* 2 V y 



OFB is a, parabola, wUh* vertex at F 



Absolute max 



M E = 



//■ 



p 



s 



ss 



:;i I 



MOVING LOADS, 



lV 



& 



< 



?7. 






c 






1 - Span. W, W„ W 2 = Concentrated Loads. w = Load per Foot. 

i:., I.',, II, . R D = Reactions at I ». B, C, I>. s„, s,. s x = Shearing Forces at O, Band Section Distant .■ 

M E , M P , M x Bending Moments at E, P and Section Distant x. 
./■ in all cases is measured from the left support towards the right 



(3) Two Concentrated Loads \V, and II". at fixed distaix- (a ■+ b). 

Sheaeinq For* b: '»]•'= \ g 

(1) Positive Shear. 

The greatest positive shearing force occurs when either 
W, or W 2 is immediately to the right of the section. 

T~ [*-"> 



SYSTEM OF LOADING 
y i£ centre of gravity of foods 

= W 7 (a + b) 
Wf + Wz 

b W 1 + W 2 



For sections between • » and F, S x = i;„ = 



C17— tHh) *-* C For sections between F and C, S x = ^ c 

*k==^&Pn?i j«c (2 ) Negative Shear. 

The greatest negative shearing force at any section 

occurs wrhen either W, or W 2 is immediately to the left oi 

tin- section. 



MAXIMUM SHEARING FORCE DIAGRAM. 



^ 



•JV, 



/»; 



js^^m, 



etfte 



a + 



<V, 



r pr 



\C 



CH-W, 
OD=W z 



-;*«? 



MAXIMUM BENDING MOMENT DIAGRAM 



2£ 



"-^ftV 



iJf-a*iS f _ r 



</J 



QR 



%l 



4 



ORC . . . . 7 



F"i Mrti..ns li.'iw.-eii <> and F. s v = _ ILL ~ 

For sections between Fand C, S a = -V w = _ W »+W ( r _ /, | 

This is a straight line ..f slope = - Wl + ^ 

The shear in front of W, = shear behind vV a but occurs 
at distance (a + 6) behind it. Also shear immediately 
behind W a differs from that in front by the amount W, ' 

Bending Moment : 

Hie maximum bending moment at any section occurs 
wh.n a load is over that section. 

' I ) I >U6 to W, over any section distant x. 

>'• - 5 ♦ 5 ( . _ , ) 

Absolute max. M x = ^' ±JZ?(j_ /, V 

' 2 ) Due tn u 'i overanj section distant a. 

■aboia. 



M x = !;,„,■ = 



/ 



ll — x — a J .'•, a pars 



Absolute max. M L = Wl + AV - ( ? _ „ 

/. a part of the diagram will be 



When (4 + b) > 






il Pa'-abola of height y due to the passage of the heavier 

oi tin- tu„i, ( a.l.s(W L . in thjg case) across the I 






^ 



R< 



MOVING LOADS. 



*Mtmi 



315 



«A1 



t¥ 






W-W 



W.T 



- 



* / 






.«.',■!** 









/ _ Span, W, "W^ W 2 = Concentrated Loads. w = Load per Foot. 

r R„ Rq Rd = Reactions at i K 1», C, 1». S , S„, S x = Shearing Forces at 0, Band Section Distant '. 

M h M,., M x = Bending Moments at E, P and Section Distant a:, 
i- in all cases is measured from the lt-ft support towards tlw right 



/4) Uniformly Distributed Load, ir per fool run, of lemjth less thou the span, 

SYSTEM OF LOADING ShEARINO FoRCE \ 







B&o£^:C 



*fefifc=»==S_- 






(1) 



MAXIMUM SHEARING FORCE DIAGRAM 



I 'usil i\ .■ Sln-ar : 

Max. positive occurs when front of Load is al A 

(a) Load partially on (r>VA- Case 3) 

w (I - ■>■)' 




Max. pos. S x = 
fb) load fully on 



2/ 



h?M ft 



HO 



HG=JN= wa, 
VBiscv parabola witii vertex alD. 



(••> 



.0 



MAXIMUM BENDING MOMENT DIAGRAM 




OQDif a parabola with vertex at Q 



At3S.0.j 



Max. DOS. S x = - t [I -*+j J 

Absolute max. j«>s. K„ = #)/ ( 2/ - a J. 

Negative Shear: 
Max. negative occurs when front of Load is at D 

(n) Load partially on 

Max. neg. S x = - ., i 

(6) Load fully <»n 

o _ "' a ( , - - } the equati. 
Max. neg. b x - ^ \- % } 

, ,. , i wa ..,,♦ bv 1> at a distance = 

a straight Line oi slope - y cut 03 ^ 2 

from 

Absolute max. neg. S„ = - 2 / \ ' ~ " / 



m to 
a 



8 for some position of 



„l occurs when 



Bending Moment: 

The maximum at .any section occurs 

the Load over that section 

wax 1 a \(l - A an 
Max. M x - -7- \ X - 2/ A / 

^_5 = Jh . that is at a section K, such that, 

DK _ CK 
. . 1C BE 

n ™ ( ■> i . a\ 
Absolute max. M, - g \~ l 



♦x 



& 




31 6 



M<>YIN<; LOADS. 






K 



* *. w r »; * % w 3 m I K 

! N D rr^< n i ^K- — \ E i J IT 



s 



*T 



A) 



X 









*£ 



</ 



*£*! 



i 

^ U_^ UJ ; p--l--}-f- Hfi ff— £i 



■ y 



I lie fa yEPQ^* 7 * C7 



v 



\ 



\ 



\ 







Flq I 




\ 



\ 



^ M / 



Qy(± 



2 

X 



( 



< 



< 



t < 



5^^ 5^,^ 



D 



wit. 



QlS 



Q 



OC "I | pT-1 



^c 



!5 ' w « 

T5T 



Maximum Bending Moment: 

^avi,v7!LXl l,lm ' , ""* 1 " 1 " T"* UUder a,, - v load °«°» wl "» *** 1-' and the centre of 

' Wh ° le ""* are ^distant from tb ntre of the span." 

*■ ■- -TS^i^s^iT 1 1 B t ject l "'" load 8y8tema *'« w - "■ w - Prod ' 

centre of gravitj of the mtem. P * "' " l!l "" ,h " Verfcical through P « ia ,1 "' Uneof lhe 
distance ,„,, I,, bisected in P ma3 " m " m *»**»« uwmenl under any load such as W. the 

centre at this point P TO j , , V" T ™ l1 "' ^^ ° f fche bflML Now place AB wi<h 

•naximun, bending moment under W VS m **"* "'" ^ """ to Al *" ' ,,,in A| ^ TheD ^ 




* I 



pg 



MOVING LOADS. 



317 



Absoldtb Maximim Bending Moments : 

The maximum bending moment it im- ■ 
of the wheel loads ie over the uoi„t ti ' i P ,°" " s tlie S P>" will take „l. , 

« 1 by making several „, n' ' J'" f° 2n * '"-->» Ldbg " „. "7 w1 '*"' ™ « «*** 

F- - ■ ** - Pape,, I holdingt , h TV* ""* °«*» * » F tft " 

systems, 4 to * u.»l , ,„ „. Taki „„ r y J, ' ' ' "'" , " u ' ls > "• ■" that there am , IT.JZ** 

the I,, hi, its centre biaeoatthe^li "" """ ° f the -*• * ST. W ^ lo ""' 

- »o Project DKd.rSLt.SS ^ ^ "' ' «K£ ' .'"'m "",' ? ,'" 

the pcsifon D 1 E , an,l the maximum bendW » """" load svste '» ■ to . the I, , , 

■ - - - «~* - - * is? rssiras "' ;: ' ::;:i ;;;; £ 

-town. Shearing Force : , " 1 '"* moment " U^ifi. 

' ! onsider the load system in F!b 2 mov.n« # 

,,e t,le resuUan ' of aJ1 *- >- - ^- ffiXK? "5 over a ^t " * « f *- '■ *■ h 

Ra rt _ ,. U C;U1 easilv be show,, t J ult if 



R + \\ 



^" a - k 

J + ^ " ~~T~ > W » W * "fll give the greatest shear 

v " + \y " - * 

/ - i <W U W, wiUgive the greatest shear 

If, however, *> a and 
R ^ W, 
/ ^ a 
K Wj 



(1) 
(2) 



W * wi,] ^^ the greatest shear 



/ 



— " > S 
a 



refer to equations (I) and (2). 



""" " ' ""' **" * — "*- «ome succeeding load is at the point 

**m* Maxmn, S IIEA1 „ng Forces : 

»•* *££?iKri 1" !,r 7" iUTOl "; a ■"- l,v • series of " iovi "° "*-> >■* -" *^ 

»"i"itely elose I ,„ ,'„ ' T"^'" - when the firat <'"' -"""» " • «ries of heavy wheel, h, 

Jo tl a i ' ' °" '" '"""' " f m0T£n 8 °"' *« "earn. 

"'• w| - ^tSSiSlP ," f 1 ' 6 T*** Wheei " W " the " rSt ° f th ° h ^ "** A « 
"ffhcrizontaJl, \ ,7 " CU ' S th<! '""''""'"' P ° Ire °"' the distonce ° " " S P*» * B is set 

' l,:i " » mtUtofl (.,,/.'•''' * r^'' '° '"' t ''° ' il,k «**■" '" S ' •'""' S «" "• "»ough pole O 
f °weforaepan II- ' ,> , linein Sab - The " S "« is tl,c ab solute marimum shearing 

uiflemncet I, , hi !' ".""' sl "" lnr| y f '"' oflw q»ns. Vote that with the same loads, but slight 

MnpBned fonn of ' i ' 7 distonces »P"I» the controlling wheel for shear might be AV„. This 

Univeisity ' "'"I"'"'' 1 construction is amplified and extended by Mr. II. Bamford, H.Bo., Glasgow 



See " 



MoTing Loads on Railway Underbridges " (\Vhitt,l„r, 1907). 



M 




- 



?Wi. 






( 



( 



( 



i 



(318) 



Influence Lines. 

Definition.— An influence line is a curve representing the variation of any function, such as 
panel load, reaction, shearing force, bending moment, or stress n a particular section of a member 
due to unit load moving over the beam or structure. It represents the change in the function 
only for the section or point considered. 



Casi l.—StTiffle Concentrated Load W. 



SYSTEM OF LOADING 







P^l r 



Shear at Section K ■ 



K 



li 



(i) x<a. 






I 



Wx 

I 



Fni jm, sit ion uf load shown 8, 



Wx W x 01 W x 1 1 



Shear influence line 



I (Mi 

be made unity. 



1 1 D 



= W x I'l if j:i. 




(ii) Oa. 



S K = - 



C 



OC-BJhujujfy 

OEKFB us tlie tnSliuvvce Urte 
tor shear at, section K, 







MOMENT INFLUENCE LINE 
2' R 




tt 



J 



0G-, 



* BHl a, 

OJBxs th* influence, lute fc 
moment at,R. 



H 



or 



W (f - x) 

I 



The shear at any section K fur any jm. sit ion of the load W 
i- the load W multiplied by the ordinate under W in that 
position. 

Maximum s K = W x KK = ^, or - W( ' f " a \ which- 

ever is greater, and occurs when load is at K. 



Bending Moment at K : 
(i) x<a. M K = w <*-*)* 



For position of load shown 



M = W (/ - a) .,- _ W x BK x ( n' _ 



K 

2 '2 



I 



= \\ x l;K 



OB 

It is convenient to make 

BK = BH. Then M K = W x 2'2. 

(ii) ■'■>,,. 



K m-^«"»i 



M K = 



= \V x K.I when load is over 



_ Wa(l-x) 
I 

Maximum M K = W "^-"> =W x K 
action K. 

The bending moment at any section K for any position of 
the load \\ is the product— W multiplied by ordinate under 

" in given position. 
















u\ 






= v 



tNFLUEJTCE LINES. 



SYSTEM OF LOADING 



Case 2. a tms «/• r» 

' r " Wf '^H *, w w , 

NC a " w a w * &c 



319 




Shear at Section K : 



5H£^« INFLUENCE LINE 




"" OC-BD-ututy 

tor shear at section K 

FOMENT INFLUENCE LINE 




(') Loads to left of K. s - 1 v ro 

under W), (ffx °*oinate 

(ii) Loads to right of K S * 

ordinate under W.) 

^--p M Loads on both sides of K s , , - 

^ '" J and (ii) above ' K = ■Wwm sun, of (i) 

Bending Moment at K .- 

W Loads to left of K. ]\r = l S " v u - 

(") Loads to right of K. M h = " s w (/ _ 

(n'i) Loads on both sides of K m 

above. V ' M * = sum °* (i) and (ii) 

For position of loads shown A/ - nxr *;«% „ 
+ (W, x 7 7) + ( \v 4 x s 8> K " ( ,X ° 0) + 0*.x6'6) 






B 



Generally : 



c,' '.''.ted 11 ? 1 T'"' y •• eCtiM ' K ll '"- t0 a series <* moving con. 

C ! "• ', ,^ "" ; " e to mom " m ""'— «■* — «-* 

The maximum bending moment at a section K mU occur 
T, 1 ;„'";' V "; 1 ''""^ aniuT «« "*"' »•* section, a,„ I ;:, 

»«..,,„„„ /,.„,/,„;, ,„„„„„, umJei . , j 

"'■■""':■ °> 'I- '■ * -/„„, /„.„„.„ „„„ ,,„„ „JZ 

rV^/* * !*» "■'' * Mi i« >—l £ n,a 

!>-■•'; -NTi,..,, ,.„ Coring L , s ^ gl6 , 

n>e maximum shear will occur at an abutment, and in 

general when the first or second of the heaviest leading wheels 

is at the abutment. (See page 317.) 



*^>*v 



320 



INFLUENCE LINES. 



[i 



< 







Cask 3. — Uniformly Distributed Moving Load w per fool. 
system of loading < :{ ") Load of Indefinite Length. 



Vf 



iiiumiiimMiiiimiiiluiHmniiiifnmHiiiimL 



01 x, 4|l 



K e J H 



SHEAR INFLUENCE LINE 








^ifrrfiaiHH 



o- 



^-^ 0C BD- umfy 
OEKFBls the influence line 
tor shear at section K 



MOMENT INFLUENCE LINE 




G 



OG-a, BH-lou 



j K== q d l_^) 



H 



OJB is the/ uxfhi&tce line/ for 



'»< Q 



moment, cct J£ . 



Shkab at Sect ioN K : 



s k = 



tr .I'- 



ll) .'' < "• "K ., J 

H) ) i ' x ( 1 ^ I " 

For position of load shown S K = — = — a> ' 

w x 01 01 

" 2 X OF 

oi ii .. G wxor 

But ((j! = - = 11 .'.S K = - x 11 = „• 

x area 1 1. 

(ii) X > rl. S K = "- [.<~ - 2 fo + 2o/]. 

In 1 1 i:\kral: 

The shear ;it any section K for any position of the load w 
(per foot run) is w x the area of the shear influence line 
diagram "/> to that position. If the front of tin* load he ]>asl 
the section the al<H»mic sum of the areas on the two -ides of 
the section must be taken. 



Maximum shear at K = 



war 

T7 



or tr 



e - «y 

■J/ 



whichever is 



great<i. 



(i) .'* < ". 



Bending Moment at Section K : 

w (/ - a) j- 



m k = 



•_•/ 



P01 ]i"-itioil «»t load shown M K -jjj- «= : 



•J/ 



x ()2'x 



KB 
OB 



*>£-»•■•% 

w x 02 x 2 2 



02 v 2 2 
02 

= //• x area 1 1 2 2. 



(11) X> a. M K - "^ P'/.r - a/ - 3*1 

In General: 

The bending moment at any section K for any position ol 
the load w (per foot run) is w x the area of the moment 
influence line diagram up t<> that position. 

(36) For a short distributed load like ef, take from 'I"' 
influence line diagram the area enclosed between the extreme 

ordinate* vertically under - and/ 



'< 



'*i 






INFLUENCE LINES. 



S5 






-%./. 



CV |6 



ShettT>InFlaeTice\ 
Lute Diagram}. 



cb 



W, 



*' 



ft 



JK 



i * r <^9 — 17 



7 



-- ^ 






. 






»* 






a, 



i% /a 



_z \z 



\fi 



9 



J 



-F9i 



Cb 6' b 



~- ■ k — 






c£*' 



3/ *«<&./ 



/%/*. 



» -*^ 



ch 



***** Diagram* 

d> 



>P 






( ! 



«e>^ 



rh 



i i 



* i 



• 



^ 



■-& 






# 



<i 



^X 



\ 



■ 

\ 



\ 



\ 



e 



<£ 



I ^ lM *™Line,forPc^po l rWv.u,cn n 

» « m &-a*c z e t j \ 

Mr^'V+fls **'*;-#■ *yh; *<?'*; 



b >' :,1 ' l 'ing th e i,r„ 1," f' / , '" ll "" mome »t at any section for any position of the loads is computed 

» h «A J-a.l, are .]/ | "^ ***** Ioad to influence line for « iven section * J '""<>- Wleie the 

»e same or a definite ratio exists between them, this process is much simplified. 

IT 



*-«, 






%£* 



^: 






322 



INFLUENCE LINKS. 














Maximum Bending Moment. — The criterion is : the average unit load od the left of the' section 
must be equal to the average unit Load on the whole -pan. The unit -»f length ma) 1"- taken as a foot 
but it is usually convenient in trusses with equal panels to take it as a panel length. The condition 
may be expressed thus. Consider a section at -\ Pig. I. Let \\'„, = sum of loads between a and 

W W 

,. \y .,,,,, f l oa ,ls between a and ,/'. Then for maximum bending momenl it c 



1 ' . 

j a j 



For example let W, = \Y = \Y W 4 = 2\ tons, W a = \Y„ = 1J tons. Then for maximum 

W. _ W 12 



moment at c we have, nying the position of loads shown in Fig. 1, 



= 3. 



= 3, which 



"'' "j t 

satisfies the condition. There are generally two or more positions of a given load system which -will 
satisfy the criterion. The wheels should be drawn on tracing paper and moved along the girder 
int" positions satisfying the condition. It will usually 1"' sufficient to compute i\\" or perhaps 
three separately. The greatest is taken. The criterion also gives minimum values if it is satisfied 
when a load is at a orj, Van a maximum value requires a load to be placed at a point where the angle 
in the influence line is convex upwards, and a minimum when ii is convex downwards. 

Shearing Force. — The shear in am panel for a given position of the Loads is computed b 
adding the products (ordinate under had to -hear influence line forgiven panel x load). 

Maximum Shearing Force. — The criterion is : the sum of the loads in any panel must 1 [ual 

totheaverage panel load on the girder. Let 2 W p = loads in the panel, ^ W - the total load on 

the truss, n = the number of panels ; thou ~ = - W P For anj particular wheel W placed at the 

panel point to the right of a panel there will be a maximum shear in that panel so long as the sum 

of th.- loads on the -irder s W lies between wW^and &(2 \Y + W >. That is ^ \Y is greater 
than »2 YY, and less than n (2 Y\\ + \Y i where SW,is the sum of the wheels in the panel other 
than the wheel \Y The maximum shear in a panel will usually occur when the firsl or second wheel 
is uear the beginning of that panel. 

Maximum Web Stress.— In general no load must pass the panel in question. Consider web 
member/ft Fig. 3. Let aa = /, be fche distance from the left end to the point at which a load 
"" stress ^ /^ and ez= /.the distance from the left end of the panel to the same point z. The 

condition then is 



1 W 



2 \\- - j- For the greatest counter stress, /, becomes (I - h) and / beconi 

[l U- [t is asuall 3 necessary to ph.ee a load at the pane] ,„,!,,, e and consider onlj as novh of 
n as is uecessary to satisfy the condition. 

Skkw Bri K " The case of a b "dge on the skew is treated in Figs. 2, 2a, 26, and 2c. The 

amount ol the skew is one panel length and the girder shown in full is the one treated. - is the line 
"I the moving load, and need not necessarily be along the centre of the bridge. The di mshi 

, 1L> - -'V'*" 1 -'' are si,,lilar *> "'«■ !■* except at the right-hand end where the influei of the 
skew is Lit. 



Girders with Subdivided PANBi*.--These require special consideration only for the imam 
', s, """~- w, "" h ' h " w " v,r - ma y be obtained by the methods alreadj given. Fig. 3 

ftel of . a tentative type. It should be noticed thai man, members will have the dmun, 

7, " 1 lh " loadm 8 «"" t,1( - l ongei portion of the girder and counter membe, rhen it 

ZZ«L ^T t '" [] "" ih0 ™ for l<^ing at the bottom panel pointe there will 

1 - no 3tresa '" G B - EH. The bracing maj act either of the ways indicated by dotted In 



' «k 


























<?*£* B/f/DG£. 



,VFL ' I'VCE TJNKs. 



Elevation^ of i 



ront FniAj 




-Baek Trt^s dotted,. 



e 



f -PW ? ^ .f&wr 



Z<2^ 




^f^J^cjjr^X^^ 



9 




323 






w 















LweDicup*anv. 



Jty.2b. 




% 



i c r al,c 7 z 
cdf- a,c,dtz 
de h ad,e s z 
efua, ei f z z 
fg L a ^ z 



Ame Diagram,. 





' 






"<* 



( 







324 



INFLUENCE LINES. 



I i panel DB the criterion given above may be applied. In Fig. 4 we must subtract the 
compression due to I'll as part of 1»A and a member of the trussed stringer, from the tension 
in I > 1 1 found by the application of tin.* criteri-m, and in Ki-_r. 5 the stress in AH must he 




D f B 

* Sef >Fig3. 







Fig.7. 



increased similarly. We may apply tin* criterion at once to I » II in Fig. 6. The panel length 
i- bere DF. A II in Fig. 7 is treated in the same way. The greatest stress in the rest of the 
member AD in Figs. 6 and 7 is then taken to be the same as that already found for the other 
part, but increased or decreased bj the stress in the portion dotted due to it being a part of 
the subordinate bracing. This, however, does not give the greatest maximum stress that may occur 
in AH, Fig. 6, or in I'll, Fig. 7, but the error involved will be small. 

UNIFORMLY DISTRIBUTED MOVING LOADS ON PANELLED GIRDERS. 

Bending Moment. -The influence line for any section will be similar to those in Fig. \h. 

Case (i).— Let M, moment at any pan. d point C, due to a uniform load of w per unit length 
movin - "" ,h " - ,,,,w lV " m Aw right. Take the influence line for a section at panel point C. 
Let A be the area of this influence line diagram up to an ordinal.- vertically under the front 

of the had. Then M, s= w X A. 

Case (u).— A is now the area between the ordinates at a and 6 vertically under the front 

and ha.k of the load. M, = w x A. 



Case (l) 

Load of xjixLefinjuLc 
laiqttv. 




R 



t: 



—p -h 



Fi g. 8 a. 




fcytffcssj 




Case (u) 

Loadabrp. 
sfwrterthan, 
\$, tin, span. 

Maximum Benimn,, M-.ment: 

Case(i)._The maximum bending moment for any section occurs when the load covers the 
whole span, and is equal to Jrf(* - d) whl . lv d -, the ^^ of ^ ^ ^ ^^ 
from the left end. 



** 






INFLUENCE LlN Ks 







••1 






*N 



• 



MOOS 



. 



V 'i 



iU 



+ 



:'-' 



:{25 



over 



As (he influence line would show, this equation a 
b- "..i .—■ above one on the lower L ^ « J* fo a pane] 

at any point, e.g., < ,, ls f 0Uni , ^^ f ' * *> Cx, H, etc., Fig. 8. But tn P , 

——• — < ~^ *2C£tffi£^ *»~ 

M <; = M„ + Ut yjK - M„) 
Case (ii).- The niaximum at any panel point will 
the ,,„,] point Referring to Fig. 8a, bending moinentT" *"* P ° 8i * i0n ° f the M 

This is R maximum for ,• = l '"' 1 '' i r ~ -J™ ~ m)} ~ 

t ST fttiS taws "T T - r to - - * - 

up to an or.hnate vertically under K. T ] H , n s = J ' " ea of "»» '>"W»» <«*«« a/gdmirt,, 
Case („,_ A „ now the nr „ a ,, etween (hc extreme wi . ^ ^ ^ ^ ^ 

.Maximum Shear : 

•g- • Then l, y moments about B we obtain W = "''" and , (V rn , 

5« f D J moments 

about o R **' f I L * - 

• «. - 2l (j>(« - ») + .,} . Therefore, sh ear in panel BC = s,„. . H - 

2 ' ^ 2p' The ""*""»''• »»lu a of this shear, S BC max., will occnr when 

" - P ~~:-{' '■ Then S BC ,,„„. . H . (" - »T 

'2 ii - 1 ' 

«£. ^Unzzirrf^ va,ue ; T,,e panei points ° n o,,e side °< *• p- 

™ed mi, loaded, anil those on ^ other ^ ^^ ^ fa ^ ^^ 

% — ' ** °' ^ " * " Rfr->«.- - + I> This gi „sa 

v " "e of tl«. shear than the true equation, and the difference is greatest when m = 2+J 
' s . ^ the centre of span, where it is approxin.ately equal to f for any span. 

«»(»«).— The true maximum shear in any panel will usually occur when the end of the load 
P^ects oyer i„t a panel. Referring to Fig. 8„, left hand reaction B, = ^{ P (»-»j + . - ?)\ 
'-J at pane, point = W c = g. s, K ,, h ,, an( „ CB . 8 „ . »|, (n _ m) + . . |)«_ i 

Ti * maximum shear wilJ occur for g = r/ ^ < r " 2(n " w ^ . 

2(rp - w) 



, that 









m^'9. 



( 326 ) 

Columns with Eccentric Loads. 






< 






W = Central Load. A = Area of Column. r = Radius of Gyration, P = ] | ^j 

I = Moment n ' Inertia assumed constant. E = Modulus oi Elasticity assumed uniform. 

y = Distance of Extreme Fibre from axis of bending. 
Ro, I!,. R D - Reactions at 0, C, D due to P, Mo, M„ M„ = Bending Moment at < ». A. BduetoP, 

J\ = Maximum 1'nit Stress al side of column due to direct compression. 

/._. = Maximum Unit Stress al side of column due to bending. 
J - A ±A = Maximum Total Unit Stri ss at side of column due t-» both direct and bending str< 

Note.— The Plus or Minus sign in tin- formula to be taken according as the stn - .lue 

W 

to bending is of the same kind as, or ■•! opposite kind to, — • 

A 



( \) Fixed at one end,Jrei at the other. Eca ntric Load within breadth of On column. 




DISTRfBUTWN OF STRESS OH CROSS SECT/ON 



(i) Nc Tension . 
Pwithui middle third 
of section;. 

< Wid/h oTCdmnn >* 



(RECTANGULAR) 

(ii) With Tension 
P outside middle third 
of secticTiA 




Column not deflected, 

AC-BD - *r + p 



<mdlhcf Column > 




Crlumn rut deflected SO 



CE-DG^E^, ( z= £) CE=DG 

for rectangular section.. 



Ptr 



trF-^/W+P 



t-m 



f'br rectangular seel/jm 



Reaction at base of column = W + p 

Max. BM = J 1 ,; + V ) + Wi 
, W + P 

f {F(S + p) + Wilt, 
f „ W + ] 



/ = 



__ w + p 



A~~ ± a? [ Vv + d CW + P)} for deflected column 
+ P . P»« . 



A 



Ar 



;,, when ? can he neglected. 



I 

3 






K? 



ad 



& 






- 






. mi 



to. 



- 




B 



3 



■* 



«*»»» »'T„ ECCK ,,, UC ^^ 






327 



6. 




— . -. «^ _ _- -- 



d 

J** 

Th* origin, Is at O 
**> aJl causes, andx is 
measured positive up- 
»ards,y positive tc the 
ng/u of the centre Itne 





OF = VE= & 



BH=AG 



d 

Pu 
o 



OJ-AK-p v 



Note.— The column isa^^T^ ~, j '" — J 

concerted at D. lUlt that th " *™dation reaction R D can be taken M 

d 
Shear between A and B = £? 

Shear between O and [)=.?? 

M M ,i fM ,- M ," = M% = • M;,x, ' , """« Bending Moment = + /», 
wax. deflection due to eccentric load : 



,r~ ± 5 73 I ' v + 8 0V + mfor deflected column 

A- W + p * J''y , 

^ 2 ^r^ wnen i can be neglected. 






J 



.-3* 




328 



COLUMNS WITH ECCENTRIC LOADS. 



TV = Central Load. A = Area of Column. r = Radius of Gyration. P = Eccentric Load 

I = Moment of Inertia assumed constant. E = Modulus of Elasticity assumed uniform. 

y = Distance <>f Extreme Fibre from axis of bending. 
R , R c , R D = Reactions at < », C, 1 1 due fco P. M,,. M K , M„ = Bending Moment al < >. A, B due to P 

j\ = Maximum T "nit Stress at side of column due to direct compression. 
/. = Maximum Unit Stress at side of column due to bending. 
f = J\ ± ./]. = Maximum Total Unit Stress at side of column due to b..th direct and bending stresses, 









?7i 




'<*< 



Note. — The Plus or Minus sign in the formula to be taken according as the stress due 

W 

to bending is of the same kind as, or of opposite kind to, — ■ 

A 



(3) Pin-jointed at both ends. Eccentric Load supported by brackets attached to the sid* of the column. 




SYSTEM OF LOADING. 




SHEARING FORCE DIAGRAM 
FOR J* 



G — M -H 



m 



oHb"* 

W+P 



I) 



BENDING MOME/fT DIAGRAM 
FOR P. 



LmB 



A 




O 



OD=R 



EF-JJG- 



Fir 



O 



AK 



PxTCL 



£L = 



Pre 



Vva 

1 



Vr 

R„ = Rc = j- m v = 

Maxiniuin deflection ; .,• < a. 

M ^ = V3EK at ?<****«*- v/3 

[in = 6«- - lr + 3/ (2« + 6) - 2P] 
Points of inflection : 

•'" > ". and < a + b 

rd 



M« = - 



1! 



IV 

I 



.»• = 



/ - b 



A -^-\ A,-d , ■' 



Ard 

S-^T 1 ± h I ^ + w«A h •_*/.* + * + M 

\ A 



is the deflection at point at maximum bending moment. 









■4( 



**!' | 









*H 




tf 



*'t 



COLUMNs "» «■** to AD8 






329 



Y^SfEM~OF~L04DlNO-r 




mi 2? 



IftAic 1 







°!tS m 'P i *V°i**B& at O 

OO -shift of base line 




K= + d [>*+«* + 2o* + 3c(2a + 6) l 



Mo = Pr - k c 7 

*• = F, - k o (/ _ a) 

Maximum deflection : *<„ 



r/ 



Rc = K (( - K 



m> 



Ul»». = — 



^te of inflection : 

K 



2M « a ♦ • 21W 

g Pl ; at point where a = - " " 



- OU 



( n ) •'->« and < a + o a- _ ^ + j ' y « _ ™ 

. W + P u ' "" p » - W = ° V 

A ~ Ar , ; at section of .Max. Bending Moment 

F 
'"''' 8Xpte88ion ^re assumes E uniform and J constant. 



QBSC w diagram 6r column 
pin-jointed at 

t f OO'^M 
OB Cis new base late 



Note.— For the case of anv 

jwonmiifli base at 0, and so 

<li*puse.I that its centre Jine 

remains vertical at 0, the 

same expressions will 'give 

""■values required except in 
case of R c> winch is = - R„ 

S.F. diagram : 

0>2T - OT - b, - H, 

The part O'FED 1 disap- 
pears. 



B.M, diagram : 



The part (JO'D 
pears. 



disap- 



U U 





41 ""* 



. ^\ 



[i 



?7. 










:;:;o 



COLUMNS WITH ECCENTRIC LOADS. 

















W = Central Load. A = Area of Column. r = Radius of Cyration. P = Eccentric Load 

I = Moment of Cnertia assumed constant. E = Modulus of Elasticity assumed uniform. 

_// = Distance of Extreme Fibre from axis of bending. 

];,,. ];,. i;,, = Reactions at 0, C, I > due to P. M„ ,M v , M B - Bending Moment at 0, A, B due to P. 

j\ = Maximum Unit Stress al side of column due bo direct compression. 
/", = Maximum 1 nit Stress at side of column due to bending. 

f /] ± /. Maximum Total Unit Stress ai side of column due to both direct and bending stresses, 

Note. -The Plus or Minus Bign in the formula to be taken according as the stress due 

W 
to bending is of the same kind as, or of opposite kind to, 



(5) Pinpointed at tlie bottom^ and fixed at th> top. Sea ntric Load supported by bracket attached to 

the ti</> of tic rolumn* 




SYSTEM OF LOADING 



(611) 




There will uswally be 
no point of inflection* 
between O and A (as 
shewn? in this case) if the 
bracket be near the top, 
but there may be one 
when/ it is near the 
centre of deptJv or lower 



SHEARING FORCE DIAGRAM BENDING MOMENT DIAGRAM 

FOR P. 




DQABC is base line for 
column pin jcintecL at 
00'= shift of base line 

l 



DIE- Mo 



FG-R 



o 




QRSC is diagram, for 
column, pin jointed' at 0. 

00' =M 
O'B'C is new ba&ehste 



HJ-KL-^ NC'-R, 



i;„ = 



R = - 



Note. — R d is assumed concentrated at I>. 

IV r 

- L ,/:[; WJ + ,; " ; ' + 2b a + 3 c (2 a +6)1 



Re = R - Rd 

M A - -\Vr l;„,/ - a)) 

Maximum deflection : x < a 

■ 2 M„ ! o M 

°m«. = g-yr, at point where x = 

Points of inflection : 

(i) x < a : 



Mo = - (IV - R, /) 



Xote. — For case of a column 
not continual ;il>.>vr < K .'ind so 
disposed thai its centre line 
remains vertical at ( K n< 
restrictions similar to < •'■ 



R 



.* = 



Mo 



(ii) ' > a and < (a + 6) 



Every expression here assumes 
E uniform and I constant 



/ = 



W 



y 



x = - MJ ' + V ™ _ 0IT 
P* EL6 " UU 



i U»a\. j 

j-g- "section of Max. Bending Moment. 






COU-MNS „,TH ECCE NT R1 C L0Ar ,, 



(6) /W^^^ w,, ^ , ^ 3.31 




SYSTEM OF LOADING 

w 




SMEARING FORCE DIAGRaITT^ZZ 




FOR P. 



T^-e wOL uswaUybe no \ E( ]ABC * base Jirw f or 
%**6f ufUeOavhHmm coh *™i ptn-jotnted at hoik 
d and C (as sfunvn, **"** 

™ this case) iT the 
bracket be near the top 
but there may be oru> 
when, it is near the 
centre of depth. 




tfom-K, and R, are assumed concentrated at Eand D 

v J> 'T 



ends. 

00' - shift oT base bine 

I 
&*-Mb GH~R 



The Bending Moment, 
may cross over to theneqa- 
to* (Ufh) side between £ 
and CwJien the bracket is 
near the centre of depth 

OS -Mo AT-M A 

BZ~M B cr-M$ 



j 



M. 



''" r ' 

, [P + Bc(b + 2 a) + Soft"] . K„ « -' 
i.. -J d 



/ \f - 6c - 2 ac 
[- 2 a 8 (ft + 2 c) + <*{a - b) - <f\ 

Maxi muin deflection : x< n 



Ma- 



/ 
IV 



o p i at point where x = - ^° 






Note. Forcaseofa column 
"; ,! continued beyond and 
I '. and so disposed as to re- 
main vertical at and ' ', the 
- tme expressions will give the 
values required. 

S.F. diagram : 

The parts O'GPE 1 and C^QRO 1 
disappear. 

U..V. diagram : 

The parts OSE and CYD dis- 
appear. 



M 



Poi »t* Of inflection : 

(ii > *>«, ■*!<(« + *),, = . ,v " + !^£? = 0V 

P v - I.',/- 

(iii) ./•>(« + ^ r = M c + i;,/ 
A - ~~X^' ai Section of Max, Bending Moment. 



Every expression here assumes 
E uniform and I constant. 



1 



B 




^>*v 



( 332 ) 



Portal Bracing. 



M 



& 
'<*< 














Signs: — h denotes compression, - denotes tension 

Bending Moment: 

+ convex to left ami plotti-d t<> left 
- convex to right and plotted to right. 

PORTAL BRACING. 

Mg.3. 

F K J G C P 




MAD v 





FK-CL °Ph (4f4»\ 
JTT-V l f Zsl 

shearing roncE. 

N. 




J0-GR -Fh(i-p 

BENDING MOMENT, 



The lattice portal 

I Fig. it) is approaching 
the plate girder form 
(Fig. 7). which can 
usually he taken as 
fixed at the top end. 



r 



I 4 



Id. 




FcL - be V 
SHEARING FORCE 



b 

c 



CN- fk' 

n 




Ft, - CT- Eh 




C 
T 



AY^> 



AZ 



hi 
T 



BENDING Moment Fxq.lc isforFiaxty- aZboOvAlB 



kd3* 



8-M 




F J&&6. jig q p 



Fva7. 
F 



C P 



Iigla, Fig. 7b. Fig Jc 



C K C C 




VT? 



r 



v. 



h 




c c 



f**S A] 



A^r 



SHEARING FORCE. BENDING MOMENT 



MoTE.-Anj of the cases up to Kg. II ,„,v |,„ trea.,-,1 M fixed at the base and top u well, by 
H «" expressions under ..„,„„. Coh,„„, v. ,„,,,. 3 ,s, but keep£ng „ „,„, „, , qllal ... * 



m 







>M< 



-■, ; 






,r 



f 



P °RTAL BRACING. 



333 



'-COLUMNS HINGED AT BASE. 
TOGS. I to 7 represent some common types of ,, „ , , • 
r tadge work. Other examples are KnT '" "^ - "-' "■ building, , 

' S f;-' " •» 'I'l-I.-.l a t C> including , „ ^T/' '"*» *•«« 

-"'" "» «- loa,| s h P . The rei , ctions ; " - < — tad acting at C and F. -,„. 

Btottal eqnaKone. It is convert , , ' '* **»''"'•",• ordinary 

f COmement anilsll,ii -''«.v -crate to t a,,.„-H * 

'"- "' the columns were fixed. * Slmilar to Fi « s - * and 9b if the 



v,= - v = 



PA 

p 



Maximum Bnrnnra Moment: 



M 



I 



,,, i' osts " H/ '> = J ^atBandE. 



Shearing Force: 



Shear In posts below 1; or E = II = - 

2 

HA, PA, 



above 



Stres; 



i" 



-i- : 



-v 



^sJ! , :,:: ; ' t :: l ;;;::;; i ';;; n ,:'" ;"7 n » "*■ »'■ »• rig"' "do of the leaward „os,, where the 
'■' to moment, V „ and dead and live ioada are ail compressive 

MMn.7, !" " '""'' : '' "''"' ^'" Ple diSg0aal l,m - in - " the 'liwnJa arc capable of 

J , „„;,:;,„,;';. ' to * """ i ,e ■" "^ «*■— . -> * ce * eo^e.*, 

« 4^^^ " """ "* """ h —** k — M either teosio,, 



Men 




Strea 



EB 

PA 

-'v 



l 



FB 



CB 

17,, 



/"? 



-'7 



Shear in posl be- _ PA, 
tween B and C ~ 2q 



Hi«- stress «.i FC with diagonals as compression members = 



iv, r 



1 



£1 



« 




«» -> 



£*: 



£9& 











u 



334 



PORTAL BRACING. 



In Fi^s. - ami 3 the stresses are easily found by the method of sections. 
In Fig. 4 it is usual bo assume either (n) that the stresses are all taken by that system 
of bracing in which the diagonal tics are in tension, or (A) thai the portal can be treat* d 

P 

two simply-braced portals, and calculate the stresses with a load -. Then add the results 

_ 

algebraically. Method (a) is simpler. For maximum moment, shear and stresses in 
column, see formula' under Fig. 8. 

Fig. 5. — This form is used where there is a lack of head-room The portal strut F< 
is designed as a girder to take the maximum moment, shear and direct stress. For 
maximum moment, shear and stresses in columns, use formulas already given. 



Member 



Stress 



I'd 



IV, P 



/ 1 n r 



GC 



17/ 

2l + 



JG 



r 



i:i- 



BC 



GB 



JE 



P 17/ 1 7/ 

■) 



2* 



Shear - PA(- -- 1 ) 17 I 1 - ! 

p 2s \p 2 s 



P 



V,= 



17 

/' 



PA, 



2<7 



Vh W _I7/, rf I7 ; 7 

2 8 » / 2 7 8 - '/ 7 



17, d 

7 



17,. 7 
7 



17 
- 7 Y 



+ 



17 d 17 ,/ 



•_* /> 7 2p 7 



Stress in BC > + stress in DE if s < ^. 

The maximum bending moment on FC occurs at. I andG and = 11// - Vs=Vh ( - - -). 

The diagrams of bending moment and shearing force for the columns are similai to 
Figs. %a and 8b. 

Fig 6. -Tim stresses i., the bracing or web are f.-und from the shear and in the 
Hanges from tl„- bending moment. The shear is constant, and for any section is equally 
distributed among the members cut. If n = number of systems of bracing cut l, a 

vertical section as II. then vertical component of stress s v = V» = V/ !. n,if of the 
mbeI8 : "," '" l '" si "" « ^ '" compression. The maximum compression in R 

"••' ■nr- at ( . and is ' 



So. = + 



17 



2o + 2 " *^ S0 maxillium tensile stress in FC = S w = - 



HA 



<>,q + 2 



For lower flange maximum stress in Eli s„. = + lI/l _ . Vh M . . . . tT > 

' °"b - = ± , . Maximum tensmn is at B 

i • 7 -7 

ana maximum compression at E. 



Member - 



Stress 



FJ 



2^ n' ■: 



GC 



+ 



2q\ ,J _ 



EL 



+ 



2q\ n I 



K1J 



- ],/ '(i-M 

2 <A >/ / 



Diagonal 

+ 17/7 
" npq 



Fig. 7 is a plate-girder portal. The she; 



The columns ABC and DEF may 1 ^der^d fixed along BC 



ar at any point of the girder = V, = 



Vh 



and BF. 



m 






i h 






■ 















U 
n 



•'ORTAL BRACING. 



Point 



Flange Bti 




In Kg. 8 the knee braces meet at the centre of 



.- . .^. « me Knee unices meet U the f r 

*»"* •* * tak.n as an example to 2£Th£ ^ T^" ** * * VMy common 
method of sections. ' ' *'"" h " u the 8fc «**» may be found by the 







EQUIVALENT 
BEAM 

c 



STRESS 



w \ 



71 



ent STRESS MAC, 



CPAM 

¥• *9 



2 <*n c \ J 



t — /> — ^ 



i/ 



SHEARING 
FORCE 



BENDING 
MOMENT. 



B'A 



h 



i 

leu 

i 



\ 



,n 



/i 



5f!!£?|srfffw|sH£^ 



^Lfl 



ct 



wi 



2)£ !♦!%■' 



Be 
ET 











W-* VJ 




\GB 


FG 
GC 


^t 


JC 





FK 


(7 


KJ 









'" "";;:. i:; t : 5 ^t« s, "";°" ,ike "i"" 5 take " ,onra,ts uf u — > ^ *> 

uie lett oi tne section about point F 

s„ 7 sin « _ Eh or S 0I = -5L = ?¥. 

v Oi • 1 SU1Cl 'IP 

right 01 the section about C 

S OB o sin a = - HA or S OB = - — • 

qp 

m Stress m GC. Take a section like 1 1' and take momenta about point B 

(iv) Stress in FG similarly ? 

S ro XJ*- lit/ or S Kr = - P/ '' - 

ine members shown chain-dotted receive no direct stress. 
Graphical Solution.— There is a very simple and elegant graphical method of 

»""',' these stresses. It is due to Mr. Milo 3. Ketchu.n, C.E.' Insert the framework 

*W and (JI A for the columns FD and CA respectively; H, H„ V and V, remain as 

'°'"i" and are known. Begin with a point A representing the foot of the column, and set 

TK ^' = V M snoW11, " ien °* aiR ' ^ are Stresses in correspond inn m.-uihers. 

Ihe stresses in he and ca are now easily found by closing the polygon, and others similarly, 

taking joints B, C and G iu order, finishing up at D. The dotted lines in the stress 
diagram are only auxiliary. 

"The Design of Steed Mill Buildings'' (page 99), The Engineering News Publishing 
Company, New York, 1904. 













*a.a 



**t 









336 



roRTAL BRACING. 



s 



?7t 














TO*. 



U 



IS 



II. — FIXED COLUMNS. 

Any of the previous jn.ntals might be fixed at the base. They may be considered 

as fixed by virtue of the direct stress due to vertical loads, when V x \p > M al A or I > 

17/ 
with fixed ends ; M mix =- where V = the total stress in the column. Columns with 

4 

ends fixed may be treated by the preceding formula* for hinged columns by applying the 

reactions II and V at the point of inflection and pmeeeding as before. The correct distati 

of the point of contra-flexure from the fixed end is given by i = 7 £ — - V Thi> i 

slightly greater than y, the value which is usually taken, and which is quite accurate 

a 

enough for ordinary purposes, h then becomes h - \h^ and consequently the porta] 
stresses are reduced. 

Tli«' moments at ll and E will be one-half their previous value. 

Also M A = M|, = - J = - M,, = - .M,. [f the resisting moment at A or J) < 

P j, then M A = resisting moment and point of inflection i « " K - Then use (A - i) 
instead of h in formulae for portal stresses. 



COLUMNS FIXED 




*B-t- 



PORTAL DIAGRAM IBBSP" 



7! 



OA A. T 

SHEARING 8£NDIN6 
FORCE. MOMENT. 



STRESS DIAGRAM. 
C hi k 

^JFtg.dc. IK 

/ \ /I 



* / 







A.T- 



Bhji 



H-flri 



- £ih=*) 



1 W^Jn/feefcum, ^lt*S$-*Z<*? 

For example, ii a portal of the type shown in Kg. 9 be fixed at the base, we 

shall have for stresses 

s Bfi = p ±zJ 



s 



-p-fl + /fI '' 



I 



-'</ J 



2 9 



^fb = A' sec a = 



P (h - i) s 'jr + q 



r 



The anchorage can I btained from the bending moment at the base of the column. 

It is a maximum on the windward side. Let W = direct stress from vertical I tug, 
6 = length oi base plate of column, A = area of base in square inches, I = moment 

of inertia ahout axis at right angle* to direction of wind, M = Lending moment = P J, 

d = distance between the holts, T = anchorage force. 
Then 

«-(W-Y)i + S»-O.I-^i <W _T )- _« I J 









<t 



T* 



loRTAL BRACING 



337 



«iH 









"i 




*l» 



h* 






- 






ft nd the test pressure on the masonry under the leeward edge of the plate is C = 

— H pjr-' Fig. 9 is an example with fixed ends. Tin; graphical sir.- diagram is 

A v 1 

obtained similarly to Fig. 8c. 

III.— COLUMN BASES ON DIFFERENT LEVELS. 

Fig. 10. — In this case II will not be equal fco II.. Uit will be calculated from the 
formul jiven under Fig- 10. Each column should be treated separately by first 
calculating its II, then the point of application of II it point of inflection from formula 
(Fig. 9), when the shearing force and bending moment diagrams can be got out fox each. 
They will be similar to Figs. 9a and 9b. If there be a plate girder from B to C equivalenl 
to fixing the columns at B, then 

This case can be applied to an elevated railway. 

Note. — The formulae given for Fig. 10 are ha*ed on the assumption that j- = ' 
where 3 is the deflection at the point indicated by the suffix attached to it. 

H l (h i - i.) + H</< - i[) m 
V 



11 



" 



i: 



V, = - X = 



C P 




fm & 



M & 



If Moment of [rte^^tuv' of 

QohxmrvA C. 
IfrMtmturJt- oflrvvrbucu of 
CohjjruvD F. 



V. - 



H,- 



/ h, <2h \ 
( 7, * ohJ 



2.V, 

h, (■h J *2h 1 \ 
P 






Jfij fc5VV 5 W 



H-PH 



L 



COLUMNS ON DIFFERENT LEVELS. 

IV.-CONTINUOUS PORTALS. 
If N be the number of hap, then II = H, = H, - H. - ^TT' ° nM ' ritu " 
•lumn. Let 9 be its distance from G the centre of gravity of tie columns. Then if 
V and II be the reactions, ami M the Lending moment, Yocg and Rcc 9 . But JVloc^. 
Again, let u be the reaction at unit distance from G. Then 

M = u (gr + ffi + 9> + ?"*> = n 

u ?. >r = Ph or » = ., ,, 

- V 

Firs! find k, then the reactions and stresses. 

Note I th. cohunne on the windward side of G will lb. in l-» .and tho 

on the M ride in common. In Fig. U two bey. have been hta. • 

dUpananr. given » uaiaL The bending , * and sin,,.,, force .,,,,, .,n 

,., all thne eolnmna The method of Fig. Ho is als„ due to Ketehum. 












338 



I'OKTAI. HKACIN'.. 



lV? 



SHE A RIHe 

force 



B ENDING 
MOMEN 

c 




r Iig.11. 



CONTINUOUS PORTA*.. 



EQUIVALENT 
BEAM 



If A 



CQ-Uhj 

Mr*? 



WB-Uhi Vz\ 




Bz*G-Jl 



v ^ 2 Zp 



K 



STRESS DIAGRAM. 

Fig. 11c. , 




V.-UNIFORMLY DISTRIBUTED LOAD ON PORTAL. 

It i> more correcl in the case -I' null buildings, etc., to take the load on the windward 
porta] as uniformly distributed. This has been 'Ion.- in Fig. 12. 



£ 



I 



c 













BENDING 
MOMENT. 



EQUIVALENT 
BEAM. 




SHEARING 
FQRCE. 

c 



DRr-H, xDTT 3 

D 

LoewarA Diagram. Eruls ' Assumed fi^db abA CJ?&F 

Let (nv)-K s +4K47v l + 4-hfih?, + 6 K z h° + d h hf 
(m,,h-3h?-3h 2 h f ■*- hh?-h? 




B wh (rw t 
n ~ 1 'J ' - 

■" 36 Jv, (TTVjf 



Fig.12 
' AK=M A 



'if 

WuixbmriLDwujrame. 

Let (n) - Iv, •*■ Jv 

(rvti-h/j-h/ 




2v . Kb 



M^-AK-Ht*^^)^^ 



U. tnS, I . tvTv 2 . _ I =T7 



Air r =H-4r ^H z f z M A w 



Appr-caruru^ Solution, M - %( 6 7v-r Sh t ) R, =%{ WhsJv,) 

^T^^J^JZe* ^ ^ ""»*"*• ™™ ^^ correct U 



"I 



COLUMNS SUPPORTING ROOFS. 

BendU * / Motion due to wind loads, shafts, hoists, or i or any I U which 

cm, he resolved into horizontal and vertical components. 
A bench truss ro-.f ^h as is commonly used for 50ft. or (>o ft. spans is shown, 
^ported by columns, in Fig. 1. The connection between the truss and column 

,:,llv , , ;"'""' 1 *" ;i l ** ^e6E. The following tr,,,.,,,,,,, applies to anj loads 
,l; ' ,!!, " ,> "; 1 *£ , "" il «- —1 Pressure which is kept particularly in mw. When the 
'I'l »d »> the columns are assumed hinged to the truss there is no bending mom- 



< 



PORTAL BRACING 



r^w 






r-**' 1 — 




:;:!!) 










& 



*#tp-i-i 



EO-H,h t 



' b hrh, 
DIB, 



BESTCVWUH. SHCAR 



F 

J 

Dfcff- D£-iTi 
/ OE-E(h n ) 

mMlL JDDh< 

2 Ji 

*o««r fl £W r COa , M „ 





there. This is not usually realised, fan* i. *i • ""' ^ " 0M£ " r 

;"rv" '"""" , '■'"-• '".-..■- .::::;;;.:■ f: frv - Th9i °~ ■<« 

1 T m . ■"" «W* * ride, ,1„. ,,.f ; L '" t '"' '■™"l''" **» the „•„,, 

■"'».--» tli,- |.a„el points. P.- P, = P - , . , , 1 '"' resuItant l"'" s -"'- ere taken 

' 3*2' whe * R is the resultant of all the ,,,,.1 
loads. V, = _ v - i 

,,,„,.„„, - '"-•"'■ ™""" " •■-■ T ere the di , 

2 **■ r "^ Dd{ „ 8 S" l ^S: ( = e ai w pi B) T t Eo( ' 7" ■' 

,„.„, ,. *--*"—** — — ,,,. ;„.,...„,„ 



"""'" : ""' *""-" «««fc Due to ,l„ , .oading W / - * „„ , , 

y {// ""& "> /a - A - Due to flexure, 

* - — W?< "■■• unite being pounds and inches. For explanation of ,1,1- formula see 
10 E 

Page 371, Combined Stresses. /' -/' + /• tu u i 

' '■ ~- / - ± - / '- L,1 «' «Ii:i.i,'r;mis shown are for the leeward 

S1 ^' 8ince th ^ending is greater. Again by moment* about E, IL = **! (I ,„ „ 

and EL = H + ]> ti * it ■ ; '- ; '- 

r lution 8 % follow^ are the stresses in ft* aF and 5F (Fig. I) 1, 

usual way" ^ 8tressdia ^ ffi for the ^ss can at once be drawn m the 

to Ca^L !'' r ' 1 ' l, " J "" ^ ;,t base > ,,i «^"' at top. Tins case is best treated wmilarlj 
i)i( ; y applying H and Y at the point of inflection, instead of at the basa Note 

■ * "™ = , fu-i.nl on BC + wind on A I!, where A' is the point of contra- 

^' v — TI '" "' t - : "~ '— -'— ' -"- the integration 



2 \/t~+liJi ) ~ 2~" assumption involved in «„, uiMgnuwi 

" '- ' l "'l the results which follow, is that the deflections at E and F are equal, the 
l6eward '"'«— again being treated. B = H, = | 7= -V, = I (2H-vm 2rf- ;,. 



\1 




< 






W 



& 



w 



i 



f 









340 



i OLUMNS. 









IV 



(?' - i) 

Km- the windward column, the sheai al B. R K = H , and M, = H* - ,,i, 

h - //] 2 

"- is the wind pressure per fool of heigh! of column. For the leeward column, th< 

al ''• I; ' = 2 (h - //,) (h + '2h t f and Kk = H ' + Rk ' M " = H|/ ' ;ll " lif; t! "' > " • ' x i i . ) 1 1 1 , , 
uegative moment. The maximum positive occurs at E, ami is M, -. H i/ (] ... ;, j ne 

maximum tiUv stn-ss also occurs al E, and i- ./.'. ±f l = =+ ... '- — m ']■],,. , 

.V j \\ { ft —• t ) ~ 

± 10E 
mulse -I Case [. will give the stresses in members meeting at E and F. 

Case [II.— Columns fixed at both base ind top. The poinl of inaection will 
obviously he al i -1 other values wiU be as follows for Leeward column:— 



M, = 



II, 



II,/', 



B - g h v R F _ 2~r^Z Ty ,,>l ~ "' + l: '- Tne formulae in Case I. will apply 
for stresses. 



Columns. 




i. 20 r* Afi M so 



°rj~$k VsZluZ J%^ 



300 320 3+€ 360 380 4C0 

uv same Units.) >- 






COLUMNS. 



'-41 




ULTIMATE STRENGTHS OF COLUMNS. 

THE fallowing tables are taken from « A Practical Treatise on Bridge Construction" 
byT.C. Fi.U.-r, M.I.C.K. (Chapfcei X.), and the values have been reduced to tons 

ruir QiillHIV lllOll. 



per square inch. 

/ = Length of column. 
r = Radius of gyration in same units as /. 



L— Hounded Ends. Breaking weight in tuns per square inch of sectional area, 





1 last Iron. 
32.3 


Wrought Iron. 

15.7 


Mild Steel. 


Haul st.-rl. 


20 


20.8 


30.0 


to 


99 7 
— — . i 


14.5 


19.1 


26. 1 





13.4 


12.7 


16.1 


20.3 


so 


7.9 


10.3 


12.6 


14.7 


LOO 


5. 2 


s.l 


9.6 


10.6 


1 20 


3.7 


G.3 


7.3 


7.8 


110 


2.8 


5.0 


5.7 


5.9 


160 


•> •> 


3.9 


4.5 


t.6 


180 


1.74 


3. 2 


3.6 


3.7 


•_-( .. > 


1.43 


2.63 


3.0 


3.0 


220 


1.20 


2.22 


2.5 


2.55 


240 


l.oi 


1.88 


2.1 


2.15 


260 


0,87 


1.62 


1.82 


1.85 


28C 


0.75 


1.40 


1.58 


1.5!) 


300 


0.66 


1.23 


1.38 


1.40 


320 


0.58 


1.08 


1. 22 


1.22 


340 


0.52 


1.04 


1.08 


1.09 


360 


0.46 


0.87 


0.98 


0.98 


380 


o.i •_» 


0.77 


0.N 7 


0.88 


400 


0.38 


0.70 


0.78 


0.79 






342 



c 01 UMNS, 



.V? 



& 



\ 



.< 



« 



c 



\ 








TLe ' ,la " " : ul "" 1 ' "" breaking weights have heen calculated 

= f +/- *'(p+/ r- \ft.(\ - <t,\ 

2 (1 - 0) 



IS 



/' 



'" "'"■ "™ L S '-''"' '"■« Practical Treatis, tridge C true! 

" M| "'" X ' F ° r C ° lHmns •» fixed -* "• taken aa e. , .." L, where L i, the » I 

le " S " 1 "' """■• : """ "'- '■■»«"' "Ml alent, ,..,„,..,,". „,., 




COLUMNS. 



343 



II. Fixed End*. Ih-cakii. 



B ^ht in t ons per ^^ ^ 






' '.'-t Jion 



sectional area. 



40 

tin 

80 

100 

1 20 
1 40 

160 

ls.i 

200 

220 
2 10 
260 
280 
300 

320 

50 

380 

400 



Wrought Iro,,. 



Mild Steel. 



34.7 

30.:: 

24.4 

18.7 

13.4 

9.5 

7.1 
5.6 
4.6 
3.7 

3.] 

2.54 
2.23 
1.96 

1.71 

1.52 
L.34 

1.20 
1.10 
1.01 



Hard Steel 



16.0 
15.6 

I4.!i 

13.9 

12.7 

11.3 
9.9 
8.6 
7.4 
6.3 

5.4 
4.7 
4.15 

3.66 
3.21 

2.81 
2.50 



2.27 



2.01 



■ 



L88 



21.1 
20.1 
19.3 

17.8 
16.1 

13.8 
11.8 

10.0 
8.5 
7.8 

6.2 

5.4 
4.6 
4.1 
3.66 

3.21 
2.81 

2. 15 



2.27 



2. 1 1' 



30. 7 

29.4 
27.0 
23.9 
20.3 

16.7 

Mi; 

11.2 
9.3 
7.8 

6.7 

"».6 
4.9 
4.2 
3.75 

3.26 

2.90 
2.54 

2.32 

2.14 



h * lowing a„ tl„ value, <,; the ultimate compressive stress in pounds per 



***** inch, assumed i„ calculating the foregoing. 



ll.ud Steel 



70,000 



Mild St,-, i. 



Wrought Iron. 



' ',!"' Iron 



UJ.000 



;;<;,< it io 



1000 







( 344 | 



kV5 



& 



&'• 



t 



c 



?7. 



< 













Eccentric Loads. 



muE distribution of stress on a section when acted upon l,y a normal force I', the line 
I. of action of which does not pass through the centre of gravity of the action. 



Let P 
G 

v 

A 

I 

/■ 



y = 



The norma] force 

Centre of grai itj oi the section. 

Distance of the force P from <;. 

Area of section. 

-Moment of inertia of section. 

Radius of gyration of section. 

Intrnsiiv of pressure al distance y from G 

Distance from Got the pressure /.' 





A 1"": two *W*} :il "> °PP^ite forces to be applied to the section at its centre of 
g-nty, both equal to P. The condition of equilibrium is not thus affected Th^ion 
-«» acted upon by a force P al its centre of gruvity producing uniform stress *, and a 
couple, the moment of which is IV. A 

As M- -,,!,, llum ,„,„,,„,.,, ,, v ^ ^^ ]v ^ ( ^ ^ & 

I V 

,; is jy- Therefor, the total stress at this point is 



and as] - a,-\ therefore 



/• - I + P * 



j 



'= J> 't + ^"i 



A I 1 * ?} 

Hie plus or minus sign being taken according to whether the ,t T , i , „ 

.^ uu un.tii.i tne stress due bo the moment 

*of the same kind or of opposite kind to? 

v, £2 £3 !!;",:'::;: "jr2 s t •"; ■ ■"• inc ^ bie ■•■■• «• - 

. ,-■ "8 ten «o«. the above fomula c ,„ly be applied a, longest 

;ext V *—-■"»— .„-,,,,,„„, ke3 , , xIli 

""• '-•"'■ ^~e,, s C leta = the , ljs . 

"•,.,„,..,,,',„,:;" ,, ""™ 1 .,,,,- ,,.\ 

A" 




T+SC L} 



wl ""-- v ' i - 1 ''— =■■■ ft.,,*.,,, , „„ 



f 



fc\ 






( 345 ) 

General Formula 

for Moment of Inertia, Radius of Gyration, etc., of Beams, 

Shafts, and Various Sections. 

I,, i A = Area of th.- section 

y = Distance of extreme fibre from an axis through the centre of gravity (neutraJ axis) 
I„ = Moment of inertia of section about its neutral axis 

I,, = Moment of inertia of section about another line distant "<*" from the neutral axis, and 
parallel to it 

Z = Modulus of section 

r = Radius of gyration of section 

M = Bending moment at the section (in beams, etc) 

T m = Twisting moment at the section (in shafts, etc.) 

R = Moment of resistance of section 

y = Stress on extreme fibre at distance "y" from 
neutral axis 




(*)*> 



Then I.,., = \ jr + A >/- 



V. K ' = M 



*' - 



.1 



W 



M = \\ - /- f/. 

' y ' 



y 



Routh's Rule. — It applies only to bodies having three perpendicular semi-axes of 
-Mini etry. 

Mass Volume or Area x sum of squares «»1" perpendicular 

v , , . semi-axes of symmefen 

Moment "t inertia = — — ' - • 

3, i Hi" •*) 

Denominator = 3 for rectangular bodies 

Denominator * I for elliptical bodies 

Denominator 5 for ellipsoidal bodies. 
I sample, take an elliptical area : 

V* 9 




I , = 7T h (1 X 

4 



- 



i, ,r- 



•;i 



b 



(2)+° *d» 
I = irbd x . = gl 



I :; = irbd X 
4 



(j Mfr 



7T 



bd(b*+d . 



lit 



* There are restriction to the use of this formula. Fide, for example, Uneham's 
"Mechanical Engineering," page 121, Fifth Edition. 












« 




iM 



& 



t < 






346 



PROPERTIES oF VARIOUS SECTIONS. 



Section. 



„ b ifcs^ b -*| 



> 

V 

> 

V 






1 
% 
V 
1 
\ 
\ 
| j i, J 

•I \ 


■ 

i 

k 


-A 

i 

« 

• 

• 


■ 
i 
i 

i 

i 



-X 



Square. Rectangle or 
Rliombtis. 



" i \ i 




X 



Square. Reetanple or 
RJumibas l 



* v 




Square en edqe 




Rectangle on edqe. 



rt- -• f) h 



X- 











ri _ - 






4 

d, 




i 

i 

i 
• 
i 


I 

1 




* 


1 


t 








Ljl_. 



HoIUjy, Square orRrrt/inqlr. 



M 




X-- H^-- ' 



-x 



#«///>» Squar* or, edije 



1*3*1 



Area, A 



W 



A 7 



A 



6rf 



A rf A, ,/, 



*-V 



Stance of Neutral Axis from 
Extreme Fibres. 
.V and yi . 



2 



</ 



— = 0.7076 






N 6 2 + # 



■I 



-• = 0.707 b 
J* 



< 



X0 







348 



PROPERTIES OF VARIOUS SECTIONS. 



Section. 




Equilatrrnl Tn/vttrU 




p-« s 



EqailaLwal Triangle 




Triangle. 



at-eo cr-ro g-cofg 




t-x 



Trapezoid. 



<?*}mT 



Lrea, .V. 



:; 



S 2 = 0,433 - 



. 



3 
^S-= 0.433 S 



bd 



bd 



■1 



h + /,, 



2 



Distance of Neutral Axis from 

Extreme Fibres. 

yand //,. 



y 0.5774 S 
y = 0.28878 



0.866 8 



" - 



= 



3" 



d 



b + 26, ^ 

^ =" /7T"/>, 3 

ft, + '2b 
•"' = 6 + % 



1 






»-; 



• 



■BOPBETliS OB VARIOUS 



SECTIONS. (CvntmrvUed from opposite page.) 



349 



Moment of Inertia about xx. 



0.018S 4 



Section Modulus. 

1 

^ = • 



Q.0311 S a 



Radius of Gyration 



0.2039 S 



1 






MM.-.ll N 



<4 



0.0625 S a 



0.3;.:w s 



- 






i 






6d 
36 



12 



6_^ 

4 



6» + 466 1 + 6 1 a 
36(6 + 0,) 



6 ,/-■ 

•Ji 



6d 
12 



12(6 * 260 



-i_«= 0.236 d 
718 



''_ = 0.4083 d 




f/ /■>(//- + * /W '' +/ ' ,J 

6(6 + 60 N 











:m 



PROPERTIES OF VARIOUS SECTIONS. 



■ 



I 



'C* 



'C4 




X 



X- 



Si-ctiim. 



[*-*-♦! 



'<* o t — #j 

Trapezoid. 



— X 



X 



,-6 



— X 



Trapezoid. 



.±_ 




Circle 




Hollow Circif 







•SemiarcU 



X — 




Hollow SemtarrUi. 



Ana, A. 



(6 + 6,) 3 



/ , d 



« h 



..i; i; , 



ttR 

2 



^(i:.- i; -, 



Distance of Neutral Axis tv 
Extreme Fibres. 
y and y,. 



"in 



d 



i: 



i; 



y. = 0.4244 B 



!/i = 






3 



77 



K, + 8, 



N 



I 






• 






I 



I 



,M. 






--nre n i.' VVUIOUS SFa'T1«>N'S. (Continued from opposite page.) 



351 









f/ 



(36 + &0 j .j 



(I 
(6 + 36») j._, 



tK 



M 



=(*-* 



0.1088 R' 



Section Modulus. 
1 



y 



Radius of Gyration., 

-VF 




(36 -h 60 ,., 



d 



I 36 + 6 > 
V 6(6 + 60 






/ 



y 



6 + 3 6 A 



6(6 + /<,) 



1» 
7T IV 



R 



4\ S ' 



. JV + 1; 



■ 



0.25641 



» 
v 



0.2631 U 



0.1098(R^ l-s a2s ™ 5 2l 5) 

l) R, + K. 

= 0.3(R. - i:,i:: 



















w 



& 



.c 



t c 



&* 

'<*< 






352 



Section. 




Regular flaxruion 




Rewdar He.raiic'i 




7 Tfr-X 



Heaxujonal Cell 



s-0382d t .di- 9239d e 




x-4 — Z— 



Regular Oclaqon 




Regular Octaaon. 




-r-X 



^=£.: 



t'fta/icTwI fell 



(**jv) 



PROPERTIES «>]■ VARIOUS SECTIONS 



Area, A 



"',/ ,.,,, 30 = 0.866d 

0.6495 d* 

or 
2.5980 S a 



",/,-!. m 30 = 0.866 d 
2 

or 
0.6495 d* 

or 

2.5980 S s 



ii 6495 (d, •/ . 



2d? tan 224 = 0.828 <tf 



<T 



s- 



., = <>.7»»7I ./ 



or 
4.828 S s 



0.828 rf/ 

or 
707] '/ 

or 
4.828 s- 



0.707 u/r '/ i 



Instance of Neutral Axis !„,„, 
Extreme Fibres. 
// and //,. 



2 

or 

0.433 d 



d. 

2 

or 

0.577 d 



& 
j 4 = 0.433 d 



2 



', cos22i = 0.4624 
2 



2 



2cos22i 



0.5412*2 



4 cog 22J 0.462^ 
2 



'< 




5 






*v 






! ^ :\.. 



9M 






".U3i 



... 















PROPERTIES OF VARIOUS SECTIONS. {Continued fro ppozite page.) 






0.0338 df-a 



0.055 c 

or 
0.0399 -/ ' 

or 
[MS* 



0.055 d} 

OI 

U.OM'.I!),/ ' 

1.88 S* 



0.1595 W '/'i 



,i [nertia about i - , 

1 • 


Section Modulus. 

I 

ft — _ 

•*• — *"■ 

y 


0.06 4? 

or 


1 2 4 


0.5413 S J 
or 


or 
0.078 4 


0.0338 ct 1 




0.06 d* 
or 


0.1044/ 


0.5413 S J 
or 


or 


0.0338 4,< 





353 



0.078^2 -■ 
4, 



0.1 <>'.'■/ 

OI 

O.OsfUrf/ 



0.10164 

or 
0.07984 



0.345 



4, 



Radius ol Gyration. 




0.2632 <l. 
oi 

0.2284, 



Id* - ./ ' 
0.2281 V^ * 



0.2574 
oi 

0.2370 4. 



0.257 4, 

oi 
0.23764 



0.4749 v (/i ,_, 









xx 




352 



PROPERTIES ()F VAKlnl'S SECTIONS. 



Section. 



<Li-866J e 




Rctmlar HenaQon 




r-X 



Regular He.mqcn. 




Hexanonal Ml 



s-e-382d t .di--9239d e 




X 1 L_ 



Regular Octagon 




-Tr-X 



Regular Octagon.. 




X-T-h-^— 



— X 



Octagonal fell 



~5STE 



Area. \ 



- rf*tan 30° = 0.866d 



0.6495 (df- <l 



2d tan 22| 0.828. 



'»r 



s-' 



., = (».707l d; 



or 
t.828S s 



().S L >Sr/ ( - 

or 

7071 '/ 

or 
4.828 s- 



0.707 (d d | 



Distance of Neutral Axis from 
Extreme Fibres. 



or 


4 

•> 


0.6495 tf; 


or 


or 


0.433^ 


2.5980 S s 




-tf*tan30 = 0.866d, a 




or 


tf. 


n.it'.i.W- 


2 


or 


or 

<i..~»77r/ 


2.5981 1 S 2 





„1 

t ./, = 0.433 d 



2 



- , . 22^ - 0.462rf, 



2. 



= 0.54124 



^Lcos 2 2i = 0.462<* 






|fc* 



Jw 



' 






N -i • 



'■'■'r 












I *> ^m . h 














35 i 



PROPERTIES OF VARIOUS SECTIONS. 



Seel 



ii in. 



X- 




-X 



Ellipse. 




X-i 



Ellipse. 




i.. 



Hollo* Ellipse. 




Parabola,. 



X- 




Parabola. 




— X 



Parabola. 



asnr 



A Ira, A. 



]'"' 



1 



-tbd Mi) 



•i 



\ bd 



i" 



Distan© i Neutral Axis from 
Extreme Fibres. 
V and //,. 



d 



■ 






























356 



Section. 



; J 



■f* 

I I 

I 

-.If 



r*r 



n 



Equal Angle 




X- 



Equal AnqU. 



y 
i d 

x— *--f 

i 



wn>) 



M 



!T^ 



]-t- 



I 



Unequal Angle. 






- /n--| 
I 



I. 



- d — 



^ 



Unequal Annie. 



x- 







Unequal Annie. 



rx 



v-v 

J. 



h H 



ci 

-»--LJ 




-x 



Cracifornx 



<7*j7) 



[PROPERTIES <»F VARIOUS SECTIONS. 



Al«':i, A 



t(2b i) 



l(2b -0 



f(6 + rf - /) 



«(6 + // T) 



/■(/' + d -t) 



bd - 2(6 - 6J [d - i) 



Distance of Neutral Axis from 
Exti Fihres. 

V and y,. 



v 



A- * &*-*) 



2(26- /, 
= 0.316 



//, = J'ln - 1.414 « 
y = 0.707 ((A + /) - 2n] 



-/ 



, _ f<2</, + 6) + </, s 
2(^ + 6) 



1(2 6, + <*)+V 



2 



• 



fclfii 



ibfl 



















: 






>:W 






1M 












i 



PROPERTIES OF VARIOU8 SECTIONS. (CW, ifi pposite page.) 



Moment of Inertia aboul xx 



I - „)»+6n*- {b - ')(« - 'V 

3 



I 



i« § -2(»-o*+ * ( 6 -l - ; ' ^ 



3 



r(J-m»)» + 6(j»») .(b-t)(m 



[(ft- to) +dm a - (./ - /)(/// /) : 



i h cos- a _ I, sin- a 

1 

2 ^ 

- L j, i, -I..) 

" 2(1,-1) J' 



*i <* 3 + <•' (6 - 6,) 
L2 



357 



Section Modulus. 

I 



I 



6^ + i V' 



Radius of Gyration 

- - 4 : 



/r . lb 



A 



/r\_ / ^_ 

V A _ - V L2(6 8 + ^ 



fc *■ + *(* - to 



T^M^i^MT' 7 - 0) 



ve 



-iss 



<~ * -w 



Vj 



Q -"* 



ftR I :'"..'• 'a'^ 




< 







358 



PRnPKHTIES OF VARIOUS SECTIONS 



Section 



VET 



x -* f— X 




j 



Unequal Fianaed Beam 



■ 

■ 



X— 



7 

i 

i 



u 



d 
— &* — *t ay 



x 



Unequal fianaed Beam, 




<ts eqiiiii l, 

— b , •; 



X 



x +W-— * 






J 

i 

i 

i 

- i~ 



r« 



X 



-. - dL * 



—# H — X 



r« 






* 



t «... 



— X 



IE 



« ft.-*. 
Zed 



t ; 



rf — ,. 



i 

6 



fc* 



"I" 
i 



-*-* 



v 

i 

6 



6, 



- X 



Zed. 



7K577 



Area, A. 



I>i + b x t + h.,(d-'ll) 



bt + b x t + bAd 2t) 



&, d + !>{d- t) 



b x t + b(d-t) 



2b t+ l, x {d-2t) 



■H> i + 6,(rf- 2t) 



Distance of Neutral Axis ft 
Extreme Fil.res. 
// and y,. 



2 A 



6 > 
2 

6 
2 



6rf a + (6, - /-./- 



2 



2 



* - 7 



- 



ri* 



,.• 



. 






- 



J 



- 









t 









Distane. .£ Neutral Axis from 
Extrem I 
y and y x . 





= >< ■' + -li.i when flanges 
are parallel 




= A d! 4. 2 6< when flanges 
are parallel 



Mi * 



Channel 



a-35-fbrB.SBT. 

— ttXJ 



— ° A + 26< when flanges 
are parallel 



d 



1 ■ 1 " = area of head 
« + 1 (d c) + rt * / - '•' 



when Bang liel 



Bulb 7>y 



y = 2 -L[a(2d *) + /<«* 2 '',('. 






i« 



;V 



-wher 









■ 



- 



• ..<■ 



«C ;,, 






*1W 






- 






I . 



■ 



# w* 



PROPERTIES OF VARIOUS SECTIONS. (Continued from opposite ,,„,,, \ 



foment of Inertia aboul i 



wli 



Ucos 8 « - l|>i^^ 
coa - '■> 
1 _r {dt-f)\ 

-r - t'Hl I — 


-60l 


,,, , - -tan [_ Ii _ I- 





s = slope oi flangi = ^ 



1 



,-iwhen flanges are 



lr M , ..nwlien Mange 

= \bd - *,*J llar:lllel 



&<&*+</,&.'+ '-( A 4 - &,■ 



12 



2 1 b + £ & 



wlit'ii fiances are 



i ". 



pa 



la 



llel 



s = 



1 



slope of FJange = 



•J h t 



- h >P - 



9 



8S 



b d - 6, dt 



h hen fiances are 



par 



lie! 



j|3«* , +rf 1 V+ "(*•-* 



A // 



when flangea are parallel 



" 



6 



+ 



<~ + Id',/ + ScV 1 + 



/,/ 



W + 2 6*, 



Ifo ',)-■ 



361 



I 

V 



I 
V 



y 



y 



Kaolins of Gyration. 

- ■ A 



I 



I 



A 



3 






"_e 



«hb 






^ 



^ 



^>» 



1 







I 

I 

I 



•••.liL' 



PROPERTIES <>F VARIOUS SECTIONS. 



Section. 



X- 




Square Shaft 




Recianqular .Skaft 



x- 





Hollow Round Shaft. 




Hexagonal Skaft. 



X—' 




L-- -X 



11*31} 



Octagonal Shaft 



Area, A 



htl 



rrd 



;.--., 



3 

2 flPtan 30° = 0.866 tf 

or 



2(?tan 22J* = 0.828<* a 



or 
L828S 1 



Distance of Neutral Axis f,, 
Extreme Fibres. 

." and y,. 



"in 






•< 



= 0.7078 






■> 



d, 

■> 



0.577 d 
or 
S 



0.5412d 

or 
1.3 98 









ib 






- 



- 



' 









PROPERTIES OF VAKIOUS SECTIONS. (Continued from opposite page.) 



363 



Moment oi [nertia aboul seas. 



6 



bd(b* + bP) 
12 



32 



32 



< 1. 1 2 d 1 

or 

1.0826 S 



0.11 # 

or 
3.76 s' 



Section Modulus. 

1 

z = — . 

y 



I':i4ill> of i',\ lalii.n 



- 



3 . 2 



_ = 0.2357 8' 



s = 0.208S 8 (St. Venant) 



b d s 'r + & 



Z = 



6 



I - J ' 

0.294 I - (St. Venant) 

Jb* + d 8 



7T 



d 



16 



16 d, 



0.208d* 

or 
1.0826 H 



0.20324 

or 
2.872 S 



S 



-= 0.4083 S 
6 



j 



ir + d? 



12 



= 0.2887 Jb* + '/' 



d 

s 



- = 0.3536 d 



y 



8(d, a -d/) 



0.3722d 

or 
0.6455 8 



0.3644 d 

or 
0.8824 S 






''I 



fr 



l 



.^** 



( 364 . 



Beams of Solid Cross Section. 



^« 



j 



c 



THE ordinary formulae for ascertaining the stress on the extreme fibres of a beam 'I" 
not give true results for beams of solid cross section. The maximum difference 
occurs with beams of solid section, and gradually decreases as the ion more nearly 
approaches thai .if an ordinary built-up girder, when it is so small thai it can generally 
be neglected in practice. In the case of a rectangular beam of cast ir<>n, for instance, the 
load that will actually break it is about 2J times the load thai the ordinary formula shows 
would cause a stress on the extreme fibres, equal to the ultimate strength of the material, 
as given bj direct tensile tests. The following approximate method of calculating the 
transverse strength of the class of beams above referred to will be found to results 

sufficiently accurate for most purposes. 

Let f = The ultimate resistance to direct tension. 

F = The apparent resistance to the same fore.- c;mssil by transverse stress. 
Q = A constant multiplied by /. 
Then Y _- / + Q. 

The value of Q for beams of different cross section is as follows : — 



Section, 



< '.i-t Ii mi 



Wrought Iron. 



Steel 



Rectangular 
K' • 1 1 in 1 ... 



Q 



Square (in direction of diagonal) n = 




I ' / 

I I / 

13 , 

ra ' 



1/ 



For beams of cross section varying between a solid rectangle and an ordinary built-up 

girder, such as a rail, for example, the value of < t > can 1 btained with sufficient 

accuracy by multiplying its value for the rectangular section by the area of th- 

und.-r consideration, and dividing by the area of the enclosing 

rectangle. 

The following example shows the application of the above 
method to a hull-headed rail :— 

The average of four tests, of a bull-headed rail, 5.0 in. deep 
by 2.5 in. wide, weighing 82J lh. per yard, tested as a beam of 
60in.span, gave the central load causing failure to be 35 tons, 
i-e«|iure.l the actual tensile stress obtained. 

The position of the neutral axis will be found to be 2.6 in. 
f «>mtheheai and 3.0 in. from the bottom flange of the rail, and 
,M • nl of inertia 28.5 in i 




< 




REAMS OF SOLID CROSS SECTION. 



365 



*ite 



w 



WL 



For a load of 35 tons at the centre of the CO in. span, M = = 526 inch tons, 



and aa M - F • 

525 x 3 

T77TZ- = 55.3 tons per square inch. 



28.5 



area of rail 



The value of Q in this rase is ^ / x . 

1G uiv;i "t < - 1 1 ■ • I <> s 1 1 1 ■ > rectangle. 



11 



8.05 



= 0.4 f. 



• • Q - 16 ; * 5.6 in. x 2.5 in. 

Ami as F = / + Q substituting value of Q. 

F = f + 0.4/ = 55.3 tons per square inch. 
And therefore actual tensile stress / = 39.5 tons per square inch. 
The strength of strips cut out of the bottom flange of the rail, un.l tesie-1 in <lin< t 

tension was 39 tons per square inch. 1 

Deflection <>/ Solid Hxnu*. 

Tin- anomalies presented by beams of different cross section, as regards strength, do 
not extend to their deflections, except thai the elastic range is increased, and consequently 
the maximum deflection within the elastic limit is greater than theory would indicate. 

1 -Minutes of Proceedings of the Institution of Civil Engineers;' vol. xlvi, p. 188. 



..•«- 



a>3£ 



( 366 ) 



ti 






Deflection of Framed Structures. 






A 



< 




6 




mHE deflection oi a framed structure, due to a given load, can be found eithei 
J_ analytically or graphically, when the elastic deformation of each member 
caused by the stress upon it, is known, as shown by the following examples. 
Cask I.— Required the movement of the point B o/th frame A I: I \ due to th. weight W. 

Let I = Length of any member in inches, an. 1 L = its length in feet. 
S = Total stress on the member. 
A - Gross area of member in square inches + 5 to 10 per cent, according 

'" ' h '- ''— "• '" allow for the effeel of covers, junctions, etc 
E = Modulus of elasticity, which may be taken at 12,000 tons ,„, square 

inch, it W is measured in tons. 

Then the elastic deformation of a member = — n r LS ;♦■ T ;« *«i - * 

1 ]•; A 1000 \ taken in feet. 

Suppose AJ; = to ft. and BC = 50 ft., and let the 
gross sectional area of each member be 30 and 60 square 

in " l i 1 ": pes J ,,v ' lv - KW = 1"" tons then the stress on 

A It is 133 tons, and thaf on BC = 166 tons. 

By the above formulae the deformation or h-,,,.,!,,,,;,,.. 

"' A" will be 0.178 in., and the shortening of BC wiU 
be 0.139 in. 

With any convenient scale make Be and Brf = to 

'! , ,;; l ; H ;: , ' ,, , ,n :' x *v*** , ,,,,,, „,„,,,,.,,,„,,,,„,,,,..,.;„„,,,„,, ,i„. „ 

scale > " , " Reflection oi B = 0.47 in. is obtained. 

„„,'"'; ^ ,""""'"'' "'' ''"'"'' 8 deflect ^ has i a full, described and 

, ;; ;:" ,v , """• ,""•'; lstraci '- aji,„ ,.. .„.„,„,, „,.„„,, , 

M «.-ll.»,nkl..r :,,,,. Mohr. Thefollowiug es lega , ;„, 

^X-T' """" '" ; ""'"' 1,l:,Ctiw - Considering first ,1 add; 

' lS ". L "f ^ '' "" """■ ' ^ '*' P** B o/ rte .,> A B I ' d„. to ,h ight V 

'-" Length of ,,n member i„ bobes, and I. _ it* length in feet, 
p - oW stre <* on a member due to W = 100 tons 
~ ° tre » s ^ square inch on a member due to W. 

deflection 1 " ! ul""i''"'' ■*? '" " U " i: -'" " f ' ton I' 1 '""" 1 <" "'" I"'""- 

' " •""'" "' "lllrl, lt IS ,l, sln ,l (,,,,,,,.,.,;,;„. 

rrosa area of member in square inches + 5 to 10 per cent, according to the 

•-.... t" ,l],.v f,, ,1 ffect of covers, junctions, ete. 

• - Modulus of elasbeity, which maj be taken at 12,000 tons per square inch, 
" « is measured in tons. 




i .< 



5 ' ' Pto ™* i °& °f «>e Institution of Civil Eng ecs, voL rfs, m 269. 



its, 



id 


















,i*tk 






-+>* 



:-»* 



- 



DEFLECTION OP FRAMED strictures 



I S 
YVien the elastic deformation of a member = ^-7 == 

Ji A 




1000 A 

The stresses, areas, deformation, etc., of the members under consideration will be as 
shown in the following Table : — 



Member. 


L 1 S 

r fcl Total 
Le "g th - Stress. 


A 
Area. 


V 

Si resspiT 

Square 

Inch. 


E. | "■ 


Contribution to 

Deflection 
_ Y In 

E. 


Summa- 
tion. 


A B 

BC 


ft. 

40 
50 


tons 
- 133 
+ 166 


sq. in. 

30 
60 


tons 
- 4.44 
+ 2.77 


• 

111. 
-0.178 

+ 0.139 


tons 
- 1.33 
+ 1.66 


111. 
4- 0.237 
+ 0.230 


in. 




Total movement = 0.467 



ao o -*♦ jo -h 

A, c M 'i 



The lasl column gives the deflection of the point II = 0.4G7 in., which is the same 
ill is already obtained by the graphical method. 

r II. — Required, the movement of the paint e of a cantilever a bed due to the weight \\ . 

Let the length of the cantilever he 80 ft., the l 

deptti 40 ft, and W = 200 tons. 

The stresses may be calculated on the assumption 
that the bar 1» transfers one-half of the load to /;, 
although this is not strictly correct. I hiving fixed the 
limiting stress per square inch for each member, theii 
areas can be obtained, and the following Table prepared 
for the previous example. 




-», 



Memhe 



sti » 



P 

Stress per 

Square 
Inch 



E. 



Ions 


sq. in. 


- 300 


60 


- 100 


30 


+ 300 


60 


4- 100 


30 



D 



56 J 
56| 

40 



- 100 



•jo 



in. 

- 0.20 

- 0.13 

+ 0.20 
+ 0.13 

- 0.27 

- 0.27 
4- 0.16 

+ 2.8 + 0.16 

_ 5.0 - 0.20 



i i.ntriUitinn to 
Deflection 

P I u 



111. 
+ 0.30 
+ 0.06 
+ 0.30 
+ 0.06 



+ 0.19 
+ 0.19 
+ 0.11 
+ 0.11 



- 0.5 



+ 0.10 



Total ikfl'-rtion 



Suninia 

bion. 



+- 0.72 



+ 0.60 



1.32 






«. ,, ■ , „■ i w ; n the member D not 

The required movement, therefore, of the point e is LtfJ m-i 

contributing to the deflection. contributes to 

The last colin-n in the above Table shows f^l^J 0[ ^ tm that the 
the deflection 0.72 in., and the web 0.60 m., and dispels the tncia i 
deflection of a lattice girder is but little affected by the we >. 



ve 



i& 



■/ 



-■• 



368 



DEFLECTION OF FRAMED STRUCTURES. 



l 4 











Case III. — Required the deflection at the autre qf a traced girder due to a 

distributed load. 

pSireAses du£ to distnibu tecL load cl fOOtoits-^^tr^stts cUi^ U> / Con aZ ctsurr Gf'qwdcr-- *- 



S'- V "' 








Let the span of the girder be 100 ft., its depth 10 ft., and the distribute. I loud loo tons. 

The stresses due to the distribute.! load of 100 tons must first be calculated, and the 
sectional area of all the members obtain. -.1. The stresses due to 1 ton at the centre of the 
girder, the point at which the deflection is required, must next be ascertained, to allow the 
following table to be prepared. 



Member. 



Leiigtli 



Top Buiiui 
liav 1 
2 
3 
4 
5 



s 

rotal 
Stress. 



A 
A rea. 



I' 

Stress pei 

Square 

Inch. 



r 






Bottom Boom 


Bay 


1 


» * 


2 


» 


3 


n 


4 


M 


5 


Web. 


Tie 


1 


» 


2 


n 


3 




4 


» 


5 


End Post 


Strut 


1 


H 


2 


»J 


3 


•• 


4 



ft. 

10 
10 

10 
10 
10 



tons 
+ 45 
+ 80 
4 105 
+ 120 
+ 125 



10 
10 
10 
10 

1(1 



14.14 
14.14 
14.14 
14.14 
14.14 

10 

10 

10 
10 
10 



Nil 
45 
80 

105 

120 



sin 
9 
16 
21 
24 
25 



in. 



tin 

- 50 

- 35 

- 2] 

- 7 

+ 45 

4- 35 

+ 25 

+ 15 

+ 5 



Nil 

7.5 

13.4 

17.5 

20.0 



tons 
+ 5 

+ 5 

+ 5 

+ 5 
+ 5 



Nil 

-6 

-0 
- 6 

(i 



in. 
+ 0.05 

+ 0.05 
+ 0.05 

+ 0.05 
+ 0.05 





II 




t.'l 


+ 


0. 


+ 


1. 


+ 


1. 



I ''-in ribution to 
I Reflection 



tion. 



13 
10 

7 

4.5 

1.4 

11.25 

8.75 
6.25 
3.75 
1.25 



5 
-5 
-5 
-5 
-5 

4-4 
4-4 

4-4 

4-4 
4-4 



Nil 
0.06 
0.06 
0.06 

o.ot; 



- 0.0707 

- 0.0707 

- 0.0707 
-0.0707 

- 0.0707 

+ 0.04 
+ 0.04 
+ 0.04 
+ 0.04 

+ 0.04 



Nil. 

- 0.5 

- 1.0 

- 1.5 

- 2.0 









in. 


+ 


(1.025 


+ 


0.050 


+ 


0.075 


4 


0.100 


+ 


0. 1 25 







111. 



+ 
+ 



Nil. 

0.03 

o.oi; 

0.09 



4- 0.12 



+ 0.37.") 



+ 
+ 

4 
+ 
+ 



0.707 
".707 
0.707 
0.707 
0.707 

0.5 
0.5 
0.5 

0.5 
0.5 



+ 0.05 
+ 0.05 
+ 0.05 
+ 0.05 
+ 0.05 



+ 0.02 
+ 02 
+ 0.02 
+ 0.02 
+ 0.02 



+ 0.300 



4 0.250 



Half sum 



Total deflection 



+ 0.J 



+ 1.025 

2 



+ 2.050 



The required deflection of the girder is thus found to be 2.05 in., the flanges contributing 
l.oo m., and tin- web 0.70 in. 

It should be remembered that the load of one ton, for finding the value of U fol each 



- . .. 

*11 






oiiiu! 'iir 

i 
i 



I tit 



N 



- 



DEFLECTION OP FRAMED STRUCTURES. 



3fi9 



member, must always be placed at the point of the truss, the movement of which is to he 
ascertained, and in the direction in which the movement is to he measured. 

This method of calculating deflections is fully described in "Modern Framed 
nurtures," by Johnson, Bryan and Turneaure. 

Cass 111(a). — Qra/pkical method. 

The deflection a( any panel point of the braced girder in Case III. may also be found 

VI 
by a graphical construction, when the Tables on the preceding page up to . liav«* Wen 

obtained. Consider one-half of the girtU*r only, as it is symmetrical, and letter it as 
shown. Assume thai point " is lixe-l in position, that line ah is fixed in direction, 
and th.it the motion of all points takes place relative to n. 







\ _Homon£al 
■**■ ''I ydxaplaxantnt 



\ \ 



T 



H 



m 



/< 



. i 







W\ 






. 



k 



\ 



I 

I 

I 

I 
I 

I 
I 
I 
I 
• I 



* s * 



; 



1 



i 

i 
i 

\ i 






« 



: e 



i t : 

Til 



, us 



I 
I 

* ■ 



i 
i 
i 



l)l.s|'I.A< -KMENT 
1 1 1 AG HAM. 



Take any pole a. (In this case a and & are the same 
explained under Case I., plotting elastic deformations -g-, 



paint.) Apply the principle 
having regard to sign, 



and 



Tin- .Inflection diagram 



a then obtained. The 



each panel point in succession. Cue aenecw J*^.^ displacement at that 
rtical distance from a to any panel point measures fc&e o< 3b 



i&f. 



sr»iv 





370 



IxKI'l NI'AN'T FRAMES. 



VJ 






panel point. The horizontal distance from the vertical through pole a to am panel noint 
measures the total horizontal displacemelil al thai point. Tim- «A = l'.u" [ n ; g ,1,,. 
total v«iti<-al deflection at o, and A in i- the horizontal movement of m relative toaori 

Girdert with Plate Webs. 

'I''"' analytical or graphical method described ma} I"- applied to determine approxi- 
mately th..- deflection by substituting diagonals between the vertical web stiffeners and 
applying the following empirical nil.' : Assume a stress per square inch in the substituted 
vertical and diagonal members which is the same as thai due to the verti il sheari 
on the web plate at the points of substitution. 

Riveted Girders : Actual and Theoretical Deflection. 
The difference between the actual and calculated values is due to various can * s : tl.<- 
stiffness of riveted joints and cover plates; the quality of the workmanship; and th. 
position and form of the floor, in the case oi bridges, tend to reduce the deflection. It is 
found thai the riveted web connections and join! covei plates reduce tin- deflection from 

20 l " ;: " l"' r '•''" 1 - Allowance must also be made for the additional resistance of the 
materia] of the floor. 

Deflection f>n> /■> Temperature. 

. Tl1 ;- an ^ytical or graphical method may be applied to determine the deformation 
of a ^der o r frame due fc0 a ,,_, ,,„ of ,,,,,„,,„,„,, ;lctiliU ,,,, „„_„,,,.,. M ., „.,,„,„ 

or on one flange only. Expansions take the minus sign like tensile strains. Contractions 

tak. th- plus sign like compressive strain. Th, total deformation ol am membei 
- , . _ I'/// 

is uien o, __ + n ,i t the temperature effect being expressed by the second term 

Where " " f hermal Il "" ;u ' coefficient of expansion oi the material of the member or 
l 7 eaS ; '" bn ^ l'"'- '»»« ^« 1'"'' degree rise of temperature Fahrenheit. A mean 
^ f0r J » 0-0000065 per degree Fahrenheit,* = change (rise or fall) in temperature 
m degrees Fahrenheit, and I = length of member ... inches. 



J 



< 



< 










Redundant Frames. 

rpiIK criterion of a redundant frame is that there are members ... .. which nnot 
, /' r ;' ll - ll '" I -l '•■• shortened without introducing stresses. The following are 
, "'" »* »» simple non-redundant structures : -b = 2p +1 b = •>/ - 3 ; = p + 2 
where b number of bars,, 1 = nu.nl,,. of joints, and p = number of polj , The I 
lormula shows that every simply firm structure must have an odd number of bars, in 

» "town* formula d = number of bars deficient, and «- number of bar. 
i 'i in excess. 

; De,i '-"-" t Fl '""- Redundant Frames. 

?- 2 P + l + d - b = 2p+ 1 -e. 

*-V-*-* b = y - S + e. 

J = '' T - + ,l j = p + 2 - e 

' ■ hne of symmetry be drawn through any simply firm frame .t will not cut more 






( 371 ) 



¥ 












Combined Stresses. Cross Bending and 
Direct Tension or Compression. 

IN the section on "Columns with Eccentric Loads" (pages 326 to 331) any deflec- 
tion is assumed to he so small as to be inappreciable, which would in genera] 
be the case. The treatmenl given here takes account of the deflection, introducing 

IV- 

the term ± ,77^ i" the denominator. 

In the following investigation let the units be tons and inches. 
Let / = Length of member. P = Total direct tensile 01 compressive load. 

A = Area of member. '' - Ke-centricity of P = distance from line of 

I = Moment of inertia. action to neutral axis of member. 



E = Modulus of elasticity. 



r 
/ = Unit stress on til'iv due to direct load - . 



r\ = Unit stress on fibre due to bending at section of maximum moment or maximum 
deflection. 

/'= Total maximum unit stress on extreme fibre - ./, + /» 

\l = Bending moment at point of maximum deflection due to cross bending, external 

forces, and eccentricity of direct load. 
Ma = Bending moment due to deflection = Po. 

= Distance from neutral axis to extreme fibre in tension 01 compression, whichever 

is desired 
a = Maximum deflection due to all forces acting at once. 



*> 








w pe r fjt. 




. T 



1 

1 



' ¥- 



fw<-«; 




I 



+ + 



We can put . - £ where K is , tant depending , the end conditions and 

■" I , _ . , JJV, using the plus sign for 

manner of loading. Substituting b and reducing./,- pjs 



1 ± 



KE 



compi ion and minus for tension. This formulate P^^^jiia Framed 

ction and any loading. It is deduced by Frotesso ^ r ^ ^^ QQ tlll . 

Structures," page 173, Eighth Edition. The followi g ^^ loading . 

assumption that most easea in practice will correspond elm . 



jrmz 



:^72 



STRENGTH OF RINGS AND WFB I'LATKS. 






Knd Cnmlitions oi 
Column, Beam or Bar, 



Both hinged. 

i toe hinged and one fixed. 
Both fixed. 



Values of K in 

s = &L. 



KEy, 



L 8 = !0 

24 

32 



Hinged ends will be more 
usual, and it is on the Bide of 
safety to treat the member thus. 

We then have for the total 
stress 

Mi //i 

I'/ 



' A + 



I + 



10 E 



1) 

D 



TL-io« 



Strength of Rings. 1 




(iSC 



Let W = Load to be lifted in tons, 
fj = Diameter of iron in chain, 
r = Radius <»f ring in inches, 
<t -- Diameter of iron in rino 
then d = \ rlr- 

Maximum bending moment = ■ = 0.32 Wr 
Bending moment at C, M, = ^ ~ "' 






= 0.182 Wr 



■ • * . 

fafeU 

lid 



J 



.( 



Web Plates. 

xrAiiiui-s ,„]... have ,„.,,, suggested f0l . ,„,,, aini , 1M the strength of web platea 

T M girders. The generally accepted rules are that the shearing stress p 

q . n,,l, ,,f ,.,, ss ti011 BhaU not ^ , ( , one)ia]f Qf ^^ tensiifl si|| 

'1—- b the flanges of the girder, and that the web plate shall h, 

, ' ; /Vl" i'"'^ '""' a " 1-,i,,ls "'' -" """"" I '-"'""- «* »' PO^ts not 

" ■ apart than the depth oi the girder when the unsupported width of the plate 

,.h than Sttt, tunes it s thickness, Mother „„.,„ rule is the stiffeners 

.-"!.._, lure the stress m tons ,,.,■ square inch of gross section is ., than 

-gr-, "> which d is the distance between the edges of the Sa ... 



1 + 



::. » ii , , - 



,,,..„;,' 7 " !kneM in i "" , '" s - Tl " *»•» over the bearings should be 

i '., i ■ ■ '," S '"' "' "" «"« - « ^ «* th»t the «,i' „, held up 

■' ""'> -'"-' positron to resist the -],.,„„i, forces. 



1 *i 



Engineering/ 3 voL ivii., page 494. 



■ . .,.-] 



T 






= \1 .• 




C*J 






( 373 ) 



&-■ 



Buckled Plates. 

I RUCKLED Plates are usually made From 3 it. to 6 ft. square, and \ in. to § in. 
J in thickness. They can also now be obtained in long lengths having several 
buckles to the plate. There is no reliable formula from which the strength of buckled 
Dlatea can be deduced, but the following table, based on experiments with wrought-iron 
plates 3 ft. square and 2 in. rise, securely bolted down all round, shows the loads that such 
plates will Bafelj carry. 



Thickness of Plate. 



in. 

i 

s 



■ 
- 



Weight of Plate. 



lbs. 
90 

LI 2.5 

135.0 



Safe Uniformly 
Distributed Load per 
Plate. 



Safe Uniformly 

Distributed Load per 

Square Foot. 



tens 

i.:» 
6.2 
9.0 



bona 
0.5 

l.o 



r i i i l nlftto bolted or riveted down all round, is about twice the 
The resistance rri > buckled plate, bolted 

resist mi, same plate when merely supported all round- t n_ 

are, supported the resistance is red I m th, pngto- . • W . 

Bafeload the resisfc fa buckled plate . piaet^ll j 'th. san, 

Cresting on thee mo! the plater is uni or* 4 « ^ : lV thl , niiim( , ;l r W,.,,,,,,,,. 

The buckled plates forming the floor of the bud ^^ 

are 7 ft by 3 ft. by }in. thick, and have a rise of 3§ ■ » J. , susfca incd this 

apon the crown of eaeh plate, a block of granite weighing L 7 tons, an . 

Lead will,. at injury. 

Corrugated Sheets. 

rp- ■ USA* ■'""" " " 

where L = Unsupported length of Art in inches. 
, = Thickness of sheet m inches. 

6 = Breadth of -1 t "' ' nche f , 

d = Depth of corrugation, in inches. 

„ Baking ^ight distribnted in , h. 



Strength of 



■ 

r 
E 



r = 



Maximum fiW stress per square inc 

Kadiua is inches. 
Thickness in inches. 
Modulus of elasticity, in pounds. 
Maximum deflection. 



h. 



Flat Plates. 

wm Load per square inch distributed 
a = Length in inches. 
l = Breadth in inches. 

. ii-irillfl '" "■ 

f = Fibre stirs- parauci 
4 . Fibre stress parallel to b and«^ 




ft 









r- ** 



( 



■ - ■ ^H -IX: 







::74 



(1) 



BEARING PLATE*. 



Circular Plate Supported around its Perimeter, 

1 1 7 "/•- 

J = L'2S /- 

189 „•, i 



* = 



256 I> 



(•_') Circular Plate Fixed at tlte Perimeter. 



V = 



[5 ''■/- 
256 Yj 




(3) Rectangular PlaU Fixed at its Edges. 

/« = 



6< 



//>/ 



•> 



- /„4 



1' -• + ft*)* 



r = 



a^bHv 
{a~* f &*)32 Iv 



(I) £911091 /'/„/, Fixed at its Edges. 



f- 



r = 



WW 

I ^ 

64 I> 



The strength of plates supported on the edges is about | the strength of plates fi*ed 
< '^l-fs'TlK^i,J,rJ.:] ; K.ticitatundFe S tigkeiV>s e eUn 2 a^ Mechanics. 



[( 



J 




« 






< 



T 



Bearing Plates. 



■ I ' 



11 E thickness of bearing plates may be determined an 
follows : — 

'-••' W = The total load on the plate. 
a = Length of plate 

b = Width of plate, at right aisles t-. i he paper, 
d = Thickness of plate. 

ie projecting portion of the 



Tben the load under tl 



\\ 



1 ,|; ""'" = - ■• and us momenl M = -' 

f ' .i 1 



2 a 



therefore d = l 7:;,. v „.i 

x ,/,„■ wheTe J stress per square 

inch on the plate. 



{-<;-> 



\V 




c-y 






-X— 









( 375 ) 



P 



Ball Bearings. 



ERMISSIBLE pressures for hardened tool Bteel balls running on surfaces of the 
same material. 

For balls rnuning oil flat surfaces, P = 600 J 2 . 

For lull- running in grooves of which the radius is 2/'3d, P = 1200 tP. 

r = Permissible load in pounds per ball. 

'/ = Diameter in inches. 

"Transactions of the American Society of 
Civil Engineers," vol. xxxiii. 



Roller Bearings. 



Let "• = the safe Load per lineal inch of a roller ; 

1) = the diameter of pollei ; the mean diameter being taken for conical rollers. 

Then w = 300 I). 

The above formula will give the safe load on rollers from 1 in. to 16 in. diameter, whether 
they and the plates they are placed between be cast or wrought iron or steel, it being 
hi. -.1 thai the working stress is aboul one-fifth the elastic limit stress for cast iron, and 
one-third that limit for wrought iron or steel. Should the load to be carried by the 
roller be liable to unequal distribution, so that only about one-half of the rollers carry 
the entire weight, the value of w in the above formula should aot exceed 

w = 2( 10 1 >, 
For rollers supporting swing bridges, the above formulas ma] be used for the static load, 
but only one-half the value of w should be taken for the saf. load on the rollers when 

■ 

the bridge is in motion. 

These formula? were obtained from a careful and elaborate series of experiments on 
,„ 3fc eel rollers, from 1 in. to 16 in. diameter on soft steel plates, which were undertaken 

in consequen. I the problem being one that cannot be solved analytically l-r want o 

more exacl I wledge in connection with the distribution of stress and the moduli ol 

elasticity whit h obtain incases of this kind. 1 

I ,.,,, these exper nts it <r» f .d that the elastic limit was reached when the 

load in pounds was 880 l>. , ,. Iirp 

The following safe bearing pressures „, pounds per meal jnch on roUere are 

based iperimonU b, Mr. J Christie. ("Transactions of the A nean Socufc of 

I Jivil Engineers, 1 vol xxxiii.) 



Rollers at Rest. 

400 d. 
. son t /. 



Cast iron 

Rolled oi cast steel (28 to 32 tons) - 

Axle steel (35 to 38 tons) 

Tool steel (60 tons) - 

T ° o1 >t '"" 1 ' ******** ... " v . lln , s ;lI „ for rollers and bearing surface* 

Where* fc the diameter in inches. Eh ese vai ,e value8 sh ould be used, 

of the same material j if they ai f different materials, to Lowei 



Rollers in Motion. 

200 d. 
400(7. 
500 d. 
800 d. 
1000 d. 



"Modem Framed Structures," by Johnson, Bryan 



and Tnrneaure. Wiley and Sons, 



•tnicuav.s .,> --, ■ Engineers, 1 vol. xxxii., pages 

New York. "Transactions of the American Society of Civ il togm -, 

and 305. 



W 





& 



\ 



< 









( :;:<; ) 



Bearing Pressure 

Permissible Pressures for Rotating and Sliding Sulfates. 

Intermittent. I 



(Speed Slow and 



Bearing. 



Matei ials. 



P] 

Pounds per 
Inch, 



Pivots for swin- bridges - Eaxdened tool steel on special phosphor-bronze 

Trunin. .n bearings fori . , , 

bascule bridges - -J Axlt ' Rteel on Phosphor-bronze 

( '.i-t iron on lnon/e - 
Cast iron on cast iron or rolled steel 



r*' ■ 



AYimIjjcs for cinl lifts 

Do. <1<>. 

Screws w bich transmit 

motion on projected ] Steel 

area of thread - 



! 



JIHM. 

500 

L'l.Hi 



Permissible Pressures for Ordinary Cases. {ModeraU Speeds.) 



Mat ei ial. 



Hardened steel on hardened steel ----_._ 
Hardened steel on bronze -....._"" 

Tool steel (not hardened) on bronze " 

Structural steel on bronze - ...... 

Cast iron on structural steel ----... 

Cast iron on cast iron - - 

Cast iron on crosshead slides, sped not exceeding 600 ft. per minute - 



Cranks, pins, and similar joints with alternating motions 



i 



Pin 

Pounds per 
Square Inch. 



2000 
15i iu 

900 

600 

400 

400 

Increase above 
values 

100 per ci nt. 



The above results were obtained with a steel ring of rectangular section held 
between wo east-ir Uses having their bearing surfaces, with gnn metal, 12 in. 

*"", U '" ts "'" ' !u '"" t "''- 'I''"- steel ring was held stationary, and He- discs 

rotate, at speeds fro,,, 50 to 130 revolution.* per minute. The bearing surface was oil 
trough gr,.„v„s ,„ ,,,,h ,,„,■ of ring. A load of 75 11, per square inch was ,1,, ,. „ i. 
would bear at the highesl speed without seising, and 90 lb. at the lowest speed. I , 

"",;'.'"; "' " R 1 """ ""- "'" '"twentieth at 15 11, ,„,- square inch and one-thirtieth al 7.", lb. 
wiui a cylindrical hearing the limit of press,,,,, was 100 11.. per *,,,„„■ inch « th 

Me lubrication, bul when it was lubricated on the lower side and allowed to d 

■e pressure „,,,,„.,, 6001b |M , r sii , |;||v i||rh when ^ 8urfaM ^ ^^ ^ ^ fu]] 

■ Uameter, ,f one-axth „f the circle was taken the pressure «.,, I 700 11, ,,,, >,, inch. 



I u 



transactions of the American Societ) of Civil Engineers," February, L907. 













. 









n 



.r saf 

Ml BUS. 

ipw inch 






; 






< 



f< 



'? 



BEARING PRESSURE. 



377 




(456.0) 



In a swing bridge recently constructed with a centre pivot or footstep bearing, 
1 1 in. in diameter, the upper revolving pivot pin had a convex face <»f tool steel, and the 
lower fixed cup bearing was also of tool steel with a concave face, The bearing surface 
v, is at firs! equal to the area of a circle 7 in. in diameter. The friction was excessive, and 
when the bridge was turning the grinding of the pin was verj loud. The washers were 
ih ( . n taken out and turned to make increased bearing surface, amounting to an area of a 
circle 10 in, in diameter. This, however, made only a very slight improvement ; anally 

the bottom washer was changed to phosphor bronze, 
and the bearing surface increased to that of a circle 
of 12 in. in diameter. This alteration reduced the 
friction, and the bridge now turns with grea.1 ease and 
smoothness. 

The approximate load upon the centre pivot is 250 tuns. 
7 in. diameter ; 38.5 square inches for 250 tons = 6i tons per square inch 
10 in. diameter ; 78.5 square inches for 250 tons = 3.2 tons per square inch 
12 in. diameter ; 1 13 square inches for 250 tons = 2.2 tons persquare inch 
Centre bearing railway turntables usually rest upon three loose 'Uses of sufficient 
diameter to distribute the pressure. The upper and lower discs are of hardened steel, the 
middle disc of phosphor bronze, or steel if desired. The discs are placed in a cast-steel 
oil box. A> the discs are 7 in. in diameter, and the weigh! of the turn! ible is 15 tons, and 
locomotive and tender i- 100 tons, the pressure on discs is 3 tons per square inch. 

Steel, Phosphor-bronze and Gun-metal (Slow Motion). 

The safe bearing pressure on flat surfaces of hard steel, phosphor-bronze oi gun- 
metal must not exceed 6000 lb. per square inch for static loads, or 3000 lb. per 
square inch on well lubricated surfaces in slow motion. For small surfaces, say less 
than tin. in diameter, the above pressures ma 3 be increased by one-half. When the 
pressure approaches 10,000 lb. per square inch, there is danger from abrasion. 

PhospJwr-bronze, Gun-metal, etc. (Quick Motion). 1 

Su f l' Working Pressures. Revolving Bearings. Quick Motion. 



Type of Bearing. 



Crank pins— Locomotive (alternating pressure) 

Crank pins Marine and stationary (alternating pressure) 

Railway car axles .-----"" 

' Ordinary pedestals— Gun metal 

Ordinary pedestals — Good white metal - 

( liar and thrust bearing Gun-metal - 

1 ollai and throat bearing Good white metal 

Collar and thrust bearing— Lignum vita' 

Slide blocks—! las! iron or gun-metal - 

Slide blocks < 1 1 white metal " 

,__ Gun-metal busb 



< 'ham and rope pulleys for cranes 



Maximum 

Permissible 

Pressure pes 

Square Inch, 

lh. 
1500 
600 
;',-»< i 
200 
f)00 

80 
200 

50 

80 
250 
600 to 1000 



1 "Mechanics Applied to Engineering; \>W- -*' ,a 



John Goodman. Longmans 



1904 




/? 






:;. 



ll 



._'*... 



7i 









( :\7* \ 
















Friction Experiments. 

Friction of Rest. Dry Unlubricated Surfaces (Rennie) 



l'i,---iu.' in Pounds 
per Square [neb. 




Coefficient - 


of Friction. 


Wn mghl Iron on 
Wroughi [ron. 


Wrought Iron on 
• !asi [ron. 


Steel Otl 

< last I ron 


187 


0.25 


0.28 


0.30 


22 1 


0.27 


0.29 


0.33 


336 


0.31 


0.33 


0.35 


448 


0.38 


0.37 


0.35 


560 


0.41 


0.37 


0.36 


672 


Abraded 


0.38 


0.40 


784 


Abraded 


Abrade* 1 


Abraded 



Rufh ihj Friction* 



I 'avement. 



Speed pei Houi 

in Miles. 



( Joefficient, 



1 rranite - 


2.87 






0.007 


Asphalte 


3.56 




0.0121 


Wood - 


3.34 




0.0185 


Macadam (gravelled) 


3.45 




0.0199 


Macadam (granite, 
new) - 


} 3.51 




0.0451 






Slid\ 


mi Friction. 




10 






0. 1 1 




15 






0.087 


Railway tiauk 


25 
38 

45 
50 






0.080 

0.051 
0.047 
0.010 



Resistance per Ton 

in I'uuihIs. 



17.11 
27.1 I 
41.60 
14.48 

101.09 






Brass ou 
Casl [ron. 



0.23 

21 
0.21 
0.23 
0.23 
0.23 



!;• i 



Experiments 
with omnibus 

w iili vari"U> 

loads. 

1 I ommittee of 

Society of Arts, 

Clark.) 



246 
195 

17!) 
128 

111 
90 



Slidi] ttion 
of steel tyres 
on Bteel rails 
(Westin 
and Galfr in. i 









m 






■ [! 
1' 



Diction. 

In th* 

j 

' '' ' :.. ■ 

tanntil 



For 



ca 






K 13 



! 









FRICTION EXPERIMENTS. 



379 



In experiments made with two cast-iron Wains the following values of dry sliding and 
rolling friction were obtained. The beams were 175J in. long by 5| in. broad, each 
weighing 1570 lb., and were planed to a smooth surface and accurately levelled. One 
beam was laid dry upon the other, and afterwards two rollers. 2\ in. in diameter, u.-r.. 
placed T ft. apart between them. The force required to start motion was obtained for 
different li 





Force to Start Motion. 








[ .U.I.I. 





I !i efficient 
of Friction, 


Percentage 
of Loftd. 


Remarks. 




Total. 


Pounds per Tun. 








lb. 


lb. 


lb. 








1570 


150 to 500 


650 to 716 


0.29 to 0.32 


29 to 32 


Sliding frirl inn. 


2130 


4?:> to ">»><> ">oo tn .v.»n 


0.224 to 0.263 


22 to 26 


Do. 


1570 


2.73 


3.9 


0.00174 


0.17 


Kulliny fricl ion. 


2 -J 40 


5.44 


5.44 


0.00243 


0.24 


Do. 



A f<>rc<- of 3| lb. kept 20 cwt. moving on the rollers for a distance of 45 in., giving a 
coefficient of friction of 0.001G7, or 0.16 per cent of the load. 

A pull of 1 lb. with free rollers is approximately equal to 1 cwt. with dry sliding 
friction. 

In the traversing bridge at Hull the rolling friction was about 10 lb. per ton of 
moving weight. 

In experiments with eleven American turntable swing bridges the friction showed a 
maximum of 7.94 lb per 1000 lb. weight of moving structure; one bridge showed as low 
as 3.53 lb. 

Prom experiments bj Crandall and Marston made to determine the resistance t.. 
rolling of small rollers, 1 in. to 1 in. in diameter ami li in. l»nft between three 
horizontal plates of east iron, wrought iron and steel, the following formula- were 
deduced : — 

For cast-iron plates 

Coefficient of friction = ' - ' for cast iron rollers, 



Do. 



Do. 



= °:°JJ f or vvr,, ught-iron rollers, 
Jr 

= °" 0073 for steel rollers, 
Jr 



where r = radius in inches. 

With wrought-m* plate, tht friction w« 13 per cut. greater, ....I mth *■ 

plates 13 per cent. less. 

The rollers were turned and the plates planed, but neither polished. 



& 



, \ 






•uAiv 



V* 



,-. ' ■ I * •*I'.-: I 




( 380 ) 






J 




Economical Depths of Girders. 

(!) Plate C'lrdert. 

Let x = 1 >epth of girder in inches. 
W Weigh! of girder in pounds. 

/ = Allowable working stress pei square inch on the gross area. 
t = Thickness of wi b. 
L = Extreme length of girder. 

M = Total bending moment at centre (inch-pounds). 
Then 

The weigh! of the web is ., Lte, and that of the flanges, assuming the flan 
plates are the required theoretical lengths = = 1.6 



therefore 



3 \" fx I 



and W is a minimum when x = 1.27 v/ 

The above formula is based on the assumption thai no portion of the web is 
included in the Man-.- area. If, however, the resistance of the web is considered, 



then 



If the Han-.- are of constant section throughout as in the case of a rolled joist, 
then the above formula become 

/.M 
x = 1.41 y/ . if resistance of web is neglected, 



ami 



x = 1.63 y . if resistance of web is considered. 
(2) Lattict Girders. 

In trusses of the N type the maximum stiflmess or minimum defle. is 

d /yT~2 

where d - length in foot between verticals, 
and y = numbei of bays. 



obtained when 



i 



< 




Loads on Girders in Walls. 

i^IRDERS supporting well built and bonded walls without openings are d 

VJ to rain an amount of the wall equal to an equilateral triangle whose base is 

eq , '" ,l '" s P an - This does not apply where the walls mv green or have openi 

HI tlielU. 



« 



tiro. 



( 381 



) 



Approximate W eights of Tf 



Cranes. 






£ 





I ad 
Lifted 

= \\ . 



1 Tr 



'M 



M 



" 



'■ 



L' T 



oris 



M 



■• 



:\ r 






i« 






■• 



s |>;ui of 
I Van,. 

= S. 



ft. 

20 

40 

."Ml 

20 
SO 

10 

50 
20 
30 

40 

50 



Maximum 

Weight Weight 

on End „,,,!,_ 

wheelfl Ropes, etc. 



t"l|S 

2.5 
3.0 
3.5 

l.o 

3.5 

4.o 
4.7:. 

5.5 

5.0 

6.0 

7.0 

8.0 



tons 

i 
i 
i 



i 
i 
i 

ij 
H 

H 



Weight 
of Crane 

W itl.out 

Crab, 

eti . 



tona 
1.5 



2.5 



3.75 
5.0 

1.75 
2 7.-- 
4.0 
5.25 
2.0 

3.5 

5.0 

7.0 



Centre 

"' Overhang End 

End ofCarrag, Clearance 
H heels = |; 

= A. 



ft 

4 
6 

8 

10 
4 
6 

8 

10 

4 
6 

8 

10 



= C. 



!. 



111. 



n 

n 
n 

H 

8 

8 
8 
8 






Head- 

i .'■ om 
= D. 



II. 
5 
5 
5 
5 
5 
o 
5 
5 
5 
5 
5 
5 



v- a *\ 



APPROXIMATE VTEIGHT8 OF TRAVELLING (KANKs. 







Maximum 


Weight 


Centre 








Loa.l 


Span of 


Weight 


Weight 


«»t ( Sra&e 


»t 


< ivcrliani, 
<>i ( larriac 


Bod 


II 1 

1 1 1 mm 


Lifted 

i I * 


( !rane 


on Bod 

1 ■ T 1 I 


ol ( 'rali. 


\> ithout 

i 


End 


* m • * 4 

• Clearance 


= \\ . 


= s. 


\\ heels 
= P. 


Ropes, eti 


Crab, 
etc. 


Wheels 

= A. 


- B. 


in. 


= i). 




ft. 


tons 


t"||S 


tons 


ft. 


ft. 


i 


5 Tons 


20 


7.5 


2 


2.5 


4 


1 


8 


•VI 


yj 


30 


8.5 


2 


4.0 


6 


1 


8 


— 


» 


40 


9.5 


•2 


6.0 


8 


1 


8 


H 


»1 


50 


10.5 


2 


8.0 


10 


1 


8 




7k Tons 


20 


lo.O 


3 


3.0 


4 


H 


8 


>i 


30 


Ll.fi 


.3 


5.0 


6 


n 


8 


— 


n 


40 


13.0 


3 


7.0 


8 


M 


8 


■•;. 


•• 


50 


14..-» 


3 


9.0 


10 


U 


8 


H 

VI 


10 Tons 


20 


13.5 


4 


1 ° 


6 


! i; 


8 




30 


15.5 


4 


6.0 


6 


'{ 


8 


•V, 


Jl 


40 


1 i7 • :, 


4 


8.0 


8 


M 


8 


VI 


"■ 


50 


1 18.5 


4 


10.0 


10 


1 1] 


8 


5.1 


15 Tons 


20 


j 19.0 


5 


5... 


6 


M 


8 


— 




30 


21.0 


5 


6.5 


6 


H 


8 


n 


40 


23.0 




9.0 


8 


H 


8 


5j 


M 


50 


25.0 


5 


11.0 


10 


i] 


8 


H 

6 


20 Tons 


30 


28.0 


7 


7.0 


6 


• 

1! 


S 


» 


40 


30.0 


7 


10.0 


8 


H 


8 


6 


f J 


50 


3 1 1 ( i 


i 


13.0 


10 


M 


8 


6 


H 


GO 


34.0 


7 


L6.0 


12 




8 1 


6 


25 Tons 


30 


35.0 


8 


9.0 


8 


i.i 


9 


H 


>f 


40 


37.0 


8 


12.0 


8 


■I 


!» 


6| 


» 


50 


39.0 


8 


15.0 


10 


H 


9 


— 

6{ 


n 


60 


41.0 


8 


18.0 


12 




9 


6* 
7 * 


30 Tons 


30 


41.0 


10 


10.5 


8 


9 


» 


10 


U 


10 


14.0 


8 




9 


7 '- 




50 
60 


47.0 
50.0 


10 
10 


17.5 
21.0 


10 
12 




9 
9 


7 -' 
7 '- 


•>•> Ions 


40 


50.0 


12 


15.5 


8 


— 


10 


7J 




50 


53.0 


12 


19.0 


10 


4p 

1* 


10 


■1 


M 


60 


56.0 


12 


22.5 


12 




10 




h 


70 


59.0 


12 


26.0 


14 


10 


^ 



VT4 



ptf*?. 









U'PROXIMATE WEIGHTS OF TRAVELLING CRANES 



383 



Load 

Killed 

= w. 


Span «>f 
( trane 

= S. I 


Maximum 
Weight 

on End 
Wheels 
= P. 1 


Weight 

of Crab. 

Ropes, etc 


Weight 
of Crane 

without 
Crab, 

etc. 


Centre 

of 

End 

Wheels 
= A. 

ft. 


Overhang 

)f Carriage 

= B. 


End 

Clearance 

= C. 


Head- 

Km .in 

= D. 




ft. 


tons 


tons 


tons 


ft. 


in. 


ft. 


40 Tons 


40 


57.0 


14 


17.0 


8 


u 


10 


n 


• * 


50 


60.0 


14 


20.5 


10 


u 

— 


10 


n 


«* 


60 


63.0 


14 


24.0 


12 


u 


10 


7> 




70 


66.0 


14 


27.5 


14 


!'■ 


10 


n 


M 


i 80 


69.0 1 


14 


31.0 


16 


H 


10 


H 


45 Tons 


40 


64.0 


15 


19.0 


8 


H 


12 


8 


•• 


1 .0 ; 


67.0 


15 


23.0 


10 


— 


12 


8 




60 1 


70.0 


15 


27.0 


12 


4 


12 


8 


) - 


70 


73.0 J 


15 


31.0 


14 


H 


12 


8 


11 


1 so I 


76.0 


15 


35.0 


16 


— 


12 


.8 


50 Tona 


! +o 


70.0 


17 


21.0 


8 


2 


12 


8 




50 


740 


17 


25.5 


10 


2 


12 


8 




| 60 


78.0 


17 


30.0 


12 


2 


12 


8 


n 


1 "° 


82.0 


17 


34.5 


14 


2 


12 


8 




80 


86.0 


17 


39.0 


16 


Q 


12 


8 


tiii Tons 


40 


84.0 


19 


25.0 


8 




— 


12 


H 


»i 


50 


88.0 


19 


30.0 


10 


•> 


12 


H 




60 


92.0 


19 


36.0 


12 


2 


12 


H 


» 


70 


96.0 


19 


42.0 


14 


2 


12 


H 


M 


80 


100.0 


19 


48.0 


16 




— 


12 


H 


7u 1 »ns 


40 


98.0 


22 


30.0 


8 




m 


12 


H 


• 


50 


k.il'.o 


1 22 


36.0 


10 


2 


12 


9.1 

■ 


• • 


60 


106.0 


22 


42.0 


12 


•» 


12 


H 


-■ 


70 


110.0 


22 


48.0 


14 


•> 
m 


12 


H 


•• 


, 80 


114.0 


22 


55.0 


16 


2 


12 


H 


80 T« > 


50 


116.0 


26 


40.0 


10 


3 


H 


n 

m 

n 

H 
H 

9.1 

— 


-• 


1 60 


121.0 


26 


46.0 


12 


3 


14 


•• 


70 
80 
00 


126.0 
131.0 

136.0 


26 
26 
26 


54.0 
62.0 
70.0 


14 
16 
18 


3 
3 
3 


14 
14 
14 

















■w 



. ** -. 




-•• 






:?N4 



AITKOXIMATK WEIGHTS iiF TRAVELLING CRANES. 















Lo.nl 

Lifted 
= W. 


Span of 
< 'i .me 

= s. 


Max iniuiii 

Weight 

on End 

Wheels 

= P. 


Weight 
of Crab, 

K« »!"-•?, etc 

ti ms 


Weight 
of < Irane 
without 

etc. 
1 ons 


i enl i e 
• • r 

End 
Wheels 

= A. 

ft. 


< »\ >•! baug 

"i Carriagi 

= B. 


End 
1 learam e 

= C 


I: i in 
= 1). 




It. 


tons 


ft. 


in. 


It. 


90 Tons 


50 


131.0 


30 


46.0 


1 3 


14 


1 l ° 


•• 


60 


137.0 


30 


54.0 


12 


3 


14 


10 


i* 


70 


143.0 


30 


63.0 


14 3 14 


10 


VI 


NO 


149.0 


30 


72.0 


16 3 14 


10 


•* 


90 


155.0 


30 


81.0 


18 


3 


14 


10 


100 Tons 


50 


148.0 


34 


52.0 


10 


3 


14 


10 


<« 


60 


155.0 | 


34 


62.0 


12 3 


14 


10 


VI 


70 


162.0 


34 


72.0 


11 3 


14 


10 


• • 


80 


169.0 


34 


82.0 j 


16 3 


14 


10 




90 


176.0 


3 4 


92.0 


18 3 


14 


10 


» 


1 1 10 


183.0 


34 


IllLMJ 


•Jo ;{ 


14 


10 


Rema 
data given 


ass. -Cra 


ties ii< »i g] 


Veil ill t| 


ie above 


Tables may be proporti 1 


from the 



Lai 



I Hi 

ir shop I 



T 



rtro 



[ 



1 






Distribution of Crane Wheel Loads on 
Top Flanges of Qantry Girders. 

rnilK concentrated loads from the wheels of travelling cranes are distributed i a 
1 J " n - 111 of th " [ 'V flange U the combined stiffness of the rail and 11 
distribution depends upon the sections adopted for the rail and flange, and m 
; '^'"" ,m1 to i,iv " ;l len 8<* of from four to six times the total depth of Hun. 
and rail. This vertical load must be combined with the horizontal shear in determine 
""• rivets connecting the web plate to tin- Hungc aneles. 



' 



fi 



**, 









! 



I 



\ 




Lateral Forces on Top 

Gantry Girders. 

rpllK top flanges should have sufficient width and be of such a form as will resist the 
_|_ lateial forces from cross travel of the crab or from dragging weights across 
t ; H ~ ^i,,,., ,],.,,,, To provide for these forces the flanges of each girder should be designed 
to rerisi a horizontal force of at least one-twentieth of the lifting capacity of the crane 
in addition to the direct stresses from the vertical loading. 



Water Pressure. 



a 
c 



;,,„! tlu- l'ieis of a Wi.lgc nr other 
'HI I-. pressure 01 water m iuuuwu ^.« o^. ... c r 

1 atruetaie, nay be approximate^ ascertained by the follomng formula. 



mill; pressure of water in motion on stagin 



S.n-fnr. ,n,d Bottom Velocity 0/ Rivers. 

Let p = Velocity of water at surface in inches per second, 

Velocity at bottom -(« + l)-3v* and 

Mean velocity = (« + °- 5 ) - ^ u 



then 



Obstructions in Rivers. . . weond 

,.,, V v..l,„,tv of river previoue to otatrucnn,, ,„ fee u , , 

v = s, 1 ,„„;,i. 1 , I *« «*W- ■ «P- ** 

„.. Section a of rivet tetrnchon » ^ feet, 

I: - 1:; f water caoeed by the obstruction m feet, 



llf.ll 









for© «./' H r a*er £91 Motion, 

' L*V- Velocity of current (feet .p« ^~ ufc ^ pounds per square foot, 

P = pressure on a |»lane normal to the cun 

,, = 1.8 V J for fresh water, 
" 1 r* v-for salt water. m 

' ,:;",,, „ , «. - , ■ •■"■■- - * -"" i " ■* " " 

surfaces of different form, see page 389. ■• D 













( :;s<; ) 

Wind Pressure. 

LET P = wind pressure in pounds per square foot, od a flat surface, normal to 
the direction of the wind, V = velocity In miles per hour; 

Then, according to careful experiments made in the open air al the National Phvsi 
Laboratory (P.LC.K, vol. clxxi.), P = 00032 V-. 

This formula gives the pressures for different velocities shown In the following Table- 



\ i ocil j in Mi 
per Hour. 


Pi essure per Square F k>1 
in Pounds. 

0.32 


Rem i) 1 


10 




1 rentle. 


20 




1.28 


Light br( 


30 




2.88 


Moderate wind. 


4H 




:». 1 2 


High wind. 


50 




8.00 


( iale. 


60 




11.52 


Storm. 


70 




| 15.68 


Heav) storm. 


SO 




20. 1 8 


Violent storm. 


90 




25.92 


Hurricane. 


100 




:$2.no 


Violent hurri 


120 




16.08 




11(1 




62.72 


— 



If the velocity of the wind should be variable, the resulting pressure may be con 
siderably auginontt-il. 

rhe experiments referred to above also showed that the negative pressure on the 
leewar ^ side of n triangular roof may be greater than the positive pressure on the wind- 
ward Slde ' ' ,1 "' roof "'"I"', and the negative pressure on the Leeward side of the buildii e 
,,,:iN ';" as § real as one-third of the positive pressure on the windward side. 

^experiments of Stevenson form a guide to varying pressures at dil at 
1 " v< ' ls " I ll " v s,low rh " ^aryin- vriorj,,,. ,,,' w j n ,i at differenl levels in an open space. 



I i "" above ground. 


5 
4 


9 


15 


25 


52 




6 


6 1 


G.5 


7.5 




— 


17 


18 


21 


23 


^ elocities in miles per liour. 


13 


23 


25 


:;.i 


32 




19 


L'S 


31 


35 


10 


- 


26 

13.8 


32 
21.2 


34 


37 


4:5 


Average 


22.8 


25.9 


29 1 



idt* 

lib*' 

■ 

■ • 

- id 



IlfiBWB 
I»tbl 

6x1 of the 



Im 






- 



- . 

1. 






I 



1 

-I. 






< 



. 



- 



H 



•:« 



■I I 


















««. 



WIND PRESSURE. 



::>7 



During the construction of the Forth Bridge, careful records were made of the 
wind presBurea which occurred during the years 1883 to 1890. The following particulars 

of these experiments are taken fi "Engineering," of February 28, 1890 The 

, Kxo.l gauge was n board 20 ft. long by 15 ft. hi-h, ,„■ :><»<> , t[mv , flM '. t apea 
This was placed on the top of the old castle, on the island of Inchgarvie, in the 
middle of the Firth of Forth. It was set vertically, facing east and west. In the 
centre and top cornel of this board small gauges were fixed, with separate recording 
apparatus. Each had an area of 1} square feet, and recorded local pressures from 
gusts. By the side of this board there was another gauge, at a distance of about 8 ft. 
It consisted of a circular plate, U square feet area, facing easl and west. A gauge 
of tin- -line dinnMisions, but with the disc attached to the short arm of a double 
vane, so tint it would always face the wind, was also set up. 

In the following Table the most violent galea which occurred during the construc- 
tion of the Forth Bridge are given, with the pressures recorded mi the gauges. 



RECORDS OF WIND PRESSURES OH LNOHGARVIE DURING 

VIOLENT GALES. 







Pressure in 


Pounds per 


Square FoOt. 




Direc- 
















Date. 


Revolving 


Small Fixed 


Large Fixec 


r„ 


Centre of 


Right- hand 


tion of 




< !;iuge, 


Gauge, 


< lauge, 


Lai 


#e Gauge. 


Top of Lai -' 


Wind. 




1.5 gq. ft, 


1,5 sq. ft. 
23 


300 sq. ft. 

18 


1 


.5 3q. ft. 


Gauge. 




( Ictober 27, 1884.. 


29 


> > . 


S.W. 


October 28, 1884.. 


26 


29 


19 




■ • • 




s.w. 


March L'n, IMS.", .. 


30 


25 


17 




• • . 


. > > 


w. 


lember 1, 1885 


25 


27 


1!) 




■ > . 


• • * 


w. 


March 31, 1886 ... 


26 


31 


19 




28.5 


22.0 


S.W. 


February 1, 1887... 


26 


41 


15 




• • • 




s.W. 


January 5, 1888 ... 


27 


16 


7 






■ 


s.E. 


November 17, 1888 


.35 


41 


27 




■ 


... 


w. 


November 2, 1889 


27 


34 


12 






• • • 


s.w. 


January 19, 1890.. 


27 


28 


16 






. . ■ 


s.w. 


January 21, 1*90... 
January 25, 1890.. 


26 
27 


38 
24 


15 

18 




23J 


22 ! 


w. 

S.W. by 

w. 


Average 


27.6 


29. S 


16.9 










I ■ 

Since the completion of thi. bridge, in 1890, the maximum wind pre*ures bavebeen 

recorded. Xhe wind gaugee are pi , ure solving gangee with double n ■>. • 

ree of .1 -,,,,„, feet end, The, are placed * shown in «,■ -We, * 

be theUre gaugee , al I mile, and the difference of *^£%™£ 

The higheet pressure recorded is 65 lb. per Bquare foot, on gauge -i ft ■ 

,,,,,„, .,,,. ,„„„ ,|„. ..TBuMctioM of the Junior Inetitution <A Engmeere, • 



/> 



^**- 







388 



qVEENSFERJOT. S 



WIND PRESSURE. 



POSITION OF WINO GAUGES. 



« S348' 0- 



FIFE. H. 

J 




2 J5 Heiqht of Wind Gcujlors S b abcrt'e Hiqtu Waterr 



2 



RECORDS OF STORMS AT THE FORTH BRIDGE. 

PrESSURK.s in I'.avns PKH >-.l w.Y I'oOT. 






***■* 









: - 

.T-r.- 






a *- 



k* 



r 





< 






Date. 



January 26, L901... 
Noveniber23, L901 
December L3, 1902 

January 1<». 1!><»3 . 

» * 

Januarj 31, L903.. 
March 18, L903 ... 
March 21, 1903 .. 

March l'C, I'M) i .. 

December 29, 1904 
January 21, L905. 
March 18, L905 . 
February 28, 1905 

January 1 I, Him;.. 
January 2i>, linn;.. 
February 8, L906.. 



Average ... 



25 



20 

32 

22.5 

30 

32.5 

20 

23.5 



25 



Posifciou -I Wind I rauges, 



20 

20 

jo 

22.5 

21 

32.5 
92 

20 



31 

"I 

52 



20 
10 



15 



•in 
38 

59 
55 



L0 

10 
15 

in 



l'JS.O 23.0 



:,...(» 



1 1 



..) 



_L'..» 



27 



32.5 
23 

\'l 

25 



25 



I :'..<i .so.o 



Rem i 



X... 1. 


\ .. 2. 
15 


No. ::. 


No. 1. 


WO. D. 


25 


65 


■ • ■ 


, , , 


55 


50 


60 


• ■ 1 


55 


31 


27.5 


18 


■ - • 


34 


25 


20 


60 


15 


27.5 


29 


19.5 


65 


• ■ • 


26 



Si c Sketch aben i Eoi Position 

..I I Mil.. - 



W.s.W. 
W. and S.W. 



For gale of March 15 



S.W. 



In America the building laws of Sew Fork, Boston, and Chicago require fch tee! 

buddings shall be designed for a horizontal wind pressure of 30 lb. per squan foot; 

and m recent German specifications for the design of tall chimneys, the wind press to 
be allowed for are given as follows: 

Rectangular chimneys, 26 lb. per square foot. 
Circular chimneys, 17.1 lb. per square foot. 
Octagonal chimneys, 18.4 lb. per square foot. 



hi* 






■ 



Tben 
T. 

!'. 

*; 

B 



w 

w 

I 

I 

G 

I 

K 

i' 



t< 



**? 




WIND PRESSURE. 



389 



It would appear, therefore, thai 30 lb. per square foot is sufficient pressure to 
provide foi in ordinary eases, except for buildings in very exposed positions. For 
buildings more 01 less sheltered by surrounding objects, 20 lb. per square foot is 
sufficient for the structure as a whole, where such do not exceed 30 ft. in height* 
but 30 lb. pei square foot should be allowed in designing separate portions of the 
building presenting small areas. In the design of buildings it is sufficient to assume 
an ;r ge 3teady wind pressure of 30 lb. pei square foot in estimating the wind 
load "ii any member of the framework supporting an area of 300 square feet and 
under, and reduce this pressure by 1 lb. per square foot for every 100 square feel 
in -s ( >f this amount to a minimum of 20 lb. per square toot. The building 
should, in addition, resist overturning with a steady pressure of ">0 lb. per square 
foot The uplifting effect of the \\i ml need not be cmisidered, except in the case of open 
sheds in .in exposed position. 

It has been shown by experiment that the wind pressure upon surface- more or 
- sheltered by those immediately in front of them, varies very considerably according 
to the distance apart of the surfaces, but in no case does the area affected by the 
wind exceed 1.8 times the area of the surface directly fronting the wind. 
Relative II //c/ Reaistana •■> Various Surfaces. 

The value- given by various experimenters are as follows 1 : 

Flat plate ... 

diameter 
I 'arachute (concave surface), depth = 



1 



3 

Sphere 

Elongated projectile 

I linder ... 

Wedge (base to wind) 

Wedge (edge to wind), vertex angle 90 deg. 

< lone (base to wind) 

Cone (apex to wind), vertex au-le 90 dojj. 

I me (apex to wind), vertex angle 60 deg. 



... L.2 to 2 

. . i). 30 to 0.11 
0.5 
0.54 to 0.57 
... 0.8 to 0.97 
... 0.6 to 0.7 
0.95 
0.69 to 0.72 
0.54 

... ;il)Olit 0> 



■ * • 



Lattice girdei - 

Pre saws on Inclined Surfaces : Duchemin's Formula. 

Let P = [ntensity of pressure on a plane normal to the direction of tin- wind. 

P„= [ntensitj oi nor 1 pressure on a plane inclined at angle I to the horizontal 

\\= Vertical component of normal pressure. 
I\ = Horizontal component of normal pressure. 

2 sin <> 



Then 1\, = P 



I' = P 



P. - I' 



1 + .-in-' <) 

2 sin tfcos 

1 + siirtf 
2 Bin" 




4*8" 



sin 8 1 
l6 f oUowing are the values of P rt P. and P. 



For 1* = unity, tl 

. (io.imans Mech.M.icsAppUed to Engineering, 



pag. :>"3, 1D06, 



/> 






- , ~ i* ."V 



, •• I^H 







390 



WIND PRESSURE. 









Table for Duchemin'8 Constanta for P., P. p, 



Deg. Div. De 
An S le * 5 10 1." 




I 


leg. Min. 

1 3 


Deg. 
20 


Deg. Min. 
21 48 

.653 


Deg. 
25 


Deg. 
26 


Min. 
34 


D 


P„ 


.173 .337 .48 


. 5 7 •") 


.612 


.717 


."Iw 


.800 


P, .17i' .332 .468 


.546 


.575 


.607 


.650 


.665 


.692 


P* 


.015 058 .125 | 


.182 


.209 


.•ill' 


.303 


.3:5:1 


too 


, , Deg. Miu. 
Angle e. .... 41 


1 ».-g. 1 teg. 
35 1" 


Deg. 
15 


Deg. 

:mi 


= 30 deg. 






Jiise 
Span 


An. 


9. 




.910 

.(iliii 

.584 


.943 
.667 
.667 


1 



1 




P„ 
P. 
Pa 


.848 .863 
.7<>7 .709 
.170 .496 




1 
a 

1 


di 
18 

1*1 

26 

33 


min. 
26 

is 

:it 


Example: If P = 30 lb. per square foot, andd 




41 


1\, = 30 x 0.8 = 24 


P, - 30 


x 0.69 


2 = 20.7 




'. 


15 








P* = 


31 1 


X 


0.4 = 1 2. 

















I 












:!L 



•' 



. 

u sal 10 
rifai 

a. I )■ a# . 

_• 

adc 
alaiAel 



c 



Roof Drainage. 1 



Vertical length of down pipe, about 31 ft. 6 in., with about fiv bends of 15 dq wh. 
Area of roof drained by one down pipe— 4945 squaTe feet. 

Gutter level throughout, and hydraulic gradient during flow was about 1 in 600 in a 
length of 106 ft. 



Interna] Diameter 

of Down Pipes, 

Inches. 



5 

5 
5 
5 



Fall of Level 
of Water 

in Gutter. 



Content - 
I lischai ged in 
Cubic Inches, 



6 in. to 5 in. 
5 in. to 4 in. 
4 in. t«. :>> in. 
3 in. to 2 in. 



'"' in. tu i" in. 



18,975 

is. '.1 7:. 
18,!I7.-. 
18,975 

7^, MOO 



1 H», rvf.l Mean 
Duration of Flow- 
in Seconds. 



11.5 
26.5 

37.0 
66,5 



L41.5 



1 in 



I discharge in 

< !ubic Inches 

pei Si ad. 



1650.0 
716.0 
512.8 
285 



36.4 



Fotes on Qonstruction in Mild Steel," bv EL Kdler. 



1 h 

^toploom 

ib: • 

. 
fencing 1 
Mi 

varial 
fltt 

* 

F 



< 






« 






( 891 ) 






Temperature. 

T, M , ,.,.,.,„.|- ,.f temperature in Great Britain which have been made at Greenwich 
,, , ,.,,. ,,,„,, ,.., twenty years to be only 11 deg. Fahr. below and 13 deg. 
K . lh ,. above the mean temperature. The expansion of Bteel due to this range would onlybe 
, I , :_ ,„., ioo ft The maximum annual range of shade temperature may be, 

:;:;:,..:;..•. ?*,, ^ „, ^ - .„■,,, „ w*, n« . ,-, 

lm ... „,„,,., lU ,,r,,n ally cause steel to -pan. i in. and 1 u, respechvel, n a 

■'"'„;, E X bsexved men. due to temperature of the latt.ce.ron viaduct 

'""' ,l ' ',,',,.,, ,„ Railway over the Clyde at Glasgow is only 2 in. for s length 

T';;:;v:,a",u;::,. ; ,i,inioo f , »«, ..,.=.»,,. y-*— ; 

" - [% theF °^rd^tS rinT^o r t^bu a d^ 

„,, usual to provide for expanmon and contract™ « we 

••; rjTutsri^r^t.is^ u — - 

entirely neglected. In most caa u ^ ^ 

wall steel girders o) very eons.derabl 1 ■: h, - buil(Jings 

-1, cue si be decided in accordance wrih ... owncond. ^ fa ^ 

and arches have high stresses upon !..,.. due to th «*«g 1 ^ 

« -"' »ridg«, although long.tud.nm "- ! < £ g*» of th, width of the 
h osuaUj made for expansion ana contraction m 
however great this may be. 

E,f. •/ o) T*mpe"*™> "" J/ ""' /,V ''"'""""" ""■ , , . „,,,l,,- placed so that 

' Difference of temper e betw ^^Z£^X^^ 

the top i ■ i- subject to the direct rays of the su , ^ as t ,„. Uu , m5!iK 

a um than the difference of temperature reg*temd . . th > ^ ^ ^^ , jf ,,, ltj 

, ted together either by s web plate or <>'^"'; ' iemfea tme of the structure 

distributing the I equally throughout the *a*» 1 ^ ^ ,,,,. pI0pertJ 

h always higher .1 that of the surroun dug atonoq , er ^t pressures, without 

po b, ductile Uds of dowly y.eld.»g ■ - ^ ;„„,,„,,„„ thc susses 

apparent di uti - strength, stbe token .. ■ ,.„„„,„„„„ on thfferent 

d«e to variations of temperature. Thefo. * ■ J s , and p-HyJJ- 

parts of a metallic frame fron B*"" ""'' ;.„„,„„ of themetals, 1 ■•«-■ * 

! best adapted to bring ^'\^Z ! I ^ gradual *■ *"» 

,,,„,,.,„ p^ o| the frame to adjust themsen 

upon them. 

JUc <>l Sti-wturet. . , croWn of one of thecal 
For. range of temperatu. ! 50 ** W^" , lgtll „f d f .^^S 

being 246 ft., and the versed sine - '• f „ K . „,,,„„• pari of th. 

A, L Brito. Tubular Bridge' the temperature 

_ . - , lt A Jl 





/>. 



. 







1 *. 



Tubular Bridget" by Klwm Claxt 




















392 



TKMPKRATUtE. 



found during hoi sunshine to be 120 deg. Fahr., while in winter the snow h-in- ,,„ 
the bridge was found to have a temperature of 1 6 deg. Fahr. The total rangeof temperature 
was 104 deg. Fahr. An increase of temperature of 26 deg. Fahr. (from 32 deg. to 58 dec I 
gives an increase in length of 3^ in. in the whole bridge. The expansion is thus ' iii 
f or each degree, or ,;,„!!. part of the whole length. It attains its maximum and 
minimum usually at 3 p.m. and 3 a.m. It sometimes bends 2.1 in. laterally and 24 in 
vertically when the sun shines on one side or on top of the tube. On very hotsunny 
• lays the later..] motion has been so much as 3 in., and the rise and fall 2 in. A heavj 
train deflects the tubes only ■;, in., ami a violent gale \ in. The heavies! gales do no! 
produce as much motion as ten men. The eiii-cts of the sun and n ind have reference to 
the tubes before they were connected in the towers; after they had been connected the 
heaviest gales do not vibrate them ,.,.,,■ than J in., and the sun does not move them 
more than I in. or jj in. 

The Mechanical Fora of Heat. 1 



Materials, 



iJrass, < "ast - 

Brass, Wire - 

Copper - 

Iron, Cast (in tension) - 

Iron, Cast (in compression ) 

Iron Wrought 

Inn, Wrought, Soft 

Iron Wrought, Wire 

Steel, untempereil - 

Steel, annealed 

Glass 

— 

Lead 

Tin, Cast 



Expansion or 

Contraction of 

Bar 1 Ft. Long 

for a Vai iation 

of 1 Deg. Fahr. 



Extension < >i 

' Compression 
« ause.l l.ya Load 

"f 1 Ton ,.n ,i 

Bar 1 Ft. Long 

;|| "I 1 Square Inch 

in Section. 



Force Exerted 

in Expanding or 

1 ontracting l.\ a 

Bai l Square Inch 

in Section for a 

Variation of 

1 Deg. Fahr. 



ft. 



a 



0.0000104.; i 

0.000010720 

0.000009540 

O.OOOOOCl'jo 

0.000006220 

0.000006780 

0.00000r,7>n 

0.000ooi;s.i(» 

0.000005995 
0.00000<;ssi; 

0.000050000 
0.000016200 

0.000012500 



ft. 
b 

0.0002463 

0.0001 C.i »(i 

0.0001433 
0.0001575 

0.0001 GOO 

O.0O01000 
0.00007225 

0.00(»ii:,40 
0.0000779 
0.0002240 
•'.0031584 
0.000393568 



lbs. 

c 

!I4.sm;-| 

150.0800 

149.1168 

S8. i;,7.; 

KT.Of.w 

I Mi. M ii< i 
151.8720 
212.7328 
248.6848 
L97.9936 

4!l!).'.tr,su 

11.4912 
71.1424 



\ ariation in 
remperature 

\W |iiiiv.l to 

Pi oduce a 
l 'orceoi 1 Ton 

in a Bar 

I Square Inch 

in Section. 



deg., Fahr. 
b -J- a = d 

23.6 

14.9 

15.0 

25.3 

25.7 

11.8 

14.8 

10.5 

9.9 

13.3 

L.5 

I: 

31.5 



forced be , obser ^ ed that for *• same variation of temperature, glass exerts a fcer 
*w» « expanding ami contracting than an, of the metals. 



I C< 



Expansion of Structures bj HeaV by John Kelly. 






Ik 

■kft 

fckllfiti* 

r 

■ / 
n 



Th 






imp 



V 



T 



Th 



t 



HE 



i tl, 



< 



! fc 



( 393 ) 





















Hollow Cylinders. 



Thin Hollow Cylinder. -Stresses from interna] 01 externa] thud pressure. 

Let d ■■-■ Inside diameter of cylinder in inches. 
/ = Thickness of nietal of cylinder in inches, 
p = Flnid pressure in pounds per square inch. 
f = The mean hoop-tension at A or B per 
square inch. 



Then 



• _ P "' 




lt bhe pieS sure p is external, then/ = ^/ when- d, = external diameter. 

Pot thin cylinders with closed ends the actual stress within the elastic limit is only ; 
rh:II gi verj by the above formula, owing to the longitudinal tension partly neutralising 
tl„. hoop-tension. 1 

Thin ffoUow Sphen . For a thin hollow sphere the above formulae become 

f « >" / foi internal pressure, and/= 7 j'/' forexternaJ l ,ressure - 

Thick EoUow Cylinder? 

Lot K = Externa] radius of the cylinder. 

r = Internal „ » 

p = The fluid pressure. 

/• = The maximum unit Btress at A or B. 



Thei 



j 




(*S6 * 



.• ' i- twif tin- internal pressure p is equal 
One important consequent f this equation* tl ,ti ^ ^ thl , 

to ,„ tor tl,..../, no thick,..-, however greet, «U ena . ^ ^ 

Whet 0* occurs the cylinders are construct. 

.l,,,tl .., being shrunk on the crones 

? VHA. c^^.-r-orathic k hollow^hereth^e^ 

K + 2r 8 

The Friction of Hydraulic Rams. 

t 1 1 were lii' 1 ' 1 ' . 

rpi.K experiment (fed in the following » ■ rf due to the 

I ... E Tu.t, M.I.C.E., to determine the probab ^ that th e condition, 

r_,. : , ., , .„.,: or nackinssof hydraulic rams. b ( , vi . 1 ,, lil) 



UK experiments recoraea m "" *"* nT nh&ble loss of powei u« 

... !■ Tuit, M.I.C.E., fco determine the probab ^ that th e condition, 

fric'tion of tl up leather*, or packing .d w h ^n e tested had been in everyday 

of practice might be represented, the jacks ■ io* 

. ,. _ : ^„ ff » John Goodman, page - 



might be represented, the jaw 270 (1899) 

■ , » i f -,i in Goodman, pag« -' v 
. « Mechanica Applied to Engineering, ' ££ ^ 

2 Rankine, "Civil Engineering, page — l 



i j E 




& 



^ 






ft 






I 



I 

6 



FRICTION OF HYDRA (Lie RAMS. 

us.' for some time at the Forth Bridge. The loss of power due to friction in this 
case, is given in Column 6 of the annexed Table. Again, since in practice the height 
to be raised, or the external resistance offered to its action, i- seldom uniformly 
distributed over the upper surface of tin' ram, a strip of iron i in. widi 1 ' i M 
thick, was introduced between the upper surface of the ram and the | Was 

pressing against, as shown in Fig. 1, thus representing a local load not incidine 
with the axis of the ram. The loss of power due to friction, in th -.-. with an 
unequally distributed load, Js given in Column 8 of the Table. In mosl . the 

rams were again tested after having their cup leathers renewed, and being thoroughly 
cleaned and greased. The r.-sults for loss of power dim t., friction a,v given in 
Coin in ji in. 



Fiy.1. 



Waiqht 



Fiq.2 \A&B 

' A 4k 




ft> 



11 -1 



a 



j 



ONESIDED BEARING 







\ * 3 



^ 



FLg4. 





The jacks A, l; and C, Figs. 2 and 3, were tested by placing them singly in o Wick- 
steed testing machine, arranged for experimenting on specimens in compression, and 
the pressure of water recorded that was just sufficient to cause each to raise the loaded arm 

U ' machine - Ll orfcr to (l l„ ;i j n a - 1 . •. , . 1 i . - ,- pn-ssure than ran I btained by hand 

pumps, a -mall .,a,k was inverted over one 9 in. in diameter. The latter was supplied from 
a large accumulator with water at a pressure of a 1000 lb. per square inch, and wa* 
;;' forcing the water from the jack above it to the one being tested, at a pressu* tbout 
tons per square inch. This pressure multiplier stood near the testing machine. 

in ti'stiiij. ^ large jacks it was not , ,1,1, to place them directly in the testin tchine. 

ine method adopted was to observe, <„, the application of certain V.a, Is, what pr- 

•'' "™ "' ' ' in t1 "- — •' ' b.. diameter jacks. These jacks were then placed 

■ . one ol the larger ones, in which the pressure was recorded when .. was al a able oi 

forcing the small rams in under similar conditions. 

tli _ ? aU8 ! S USed fM re S isterin g the pressures were, in all cases, tested befor. an I iter 
tin- experiments. 









. 



• 












8) 






--■ 

- 






im 






PK,CT "" OF „„,„.„,.„. 



•395 









m 


3 




4 


























- 






. 


•- 
— 


• 




" 


— 

: 


— 




Z 




— 




•• 









"5 



in. 



>\ 



sq. in. tons 

(■' 

12.66 / l« 



i 



l:\56 



:i ] 8.2J, 



g 

4 

S 



6 



:t - 

.5 -? 



- 
.- /. C -r 



: 



Si 

EC 

J. 

c 

1 



1 wt. 



• . . 



■ > 



■ • • 



10 





10 




20 


V 55.9] 


' 30 
10 




50 




60 


"J 1454 1 


15 

30 
it 




60 


/ 




n 108.09 


15 
30 



60 



21 
31J 

«J 

••'1 

lb. 

• inn 

1210 
1350 
1500 

cwt. 

1 



i 






i 

1 

m 

23 
U>. 

520 
760 

1000 



-III 

1 5 1 1 

670 

880 



10.0 
9.0 
7.9 

7:: 

6.8 

9.9 

10,6 

9.9 

9.9 



10.6 

7.7 

t - * 

7.1 
6.5 
6.7 



[8.8 

ll.l 

9.0 

7.7 



ll.l 
5.5 

1.8 

3.1 



KDRAULIC tests 



8 






- § a 

3(1 =5 



fill 

* 3C *tf *ia 



cwt 

ln» 

20| 
30| 
11 

51 

n 

-I.', 

32 

I:' 



52 



— 



z 



X 

J. 



lb. 

[230 
1380 
1530 

cwt. 
I 

8 
12 
L6 
19| 
23| 

lb. 

300 
5 1 5 

790 
1030 



250 

170 
690 
920 



9.8 
7.5 

6.8 

7.5 

7.1 

13.] 

ll.l 
10.4 

9.0 

8.1 



14.1' 

12.1 

11.9 

11.7 

10.6 
10.6 
10.*; 
[0.6 
9.4 

10.1 

23.2 
1 5. 1 
12.5 
L0.5 



10 



15.0 

9.6 
7.6 
7.6 



BJJPj 

_ • 

£©32 

so ;H n rv - 

i* o* jj ~ be 

.- /. L ^ .= 



0) 

u 

- 

K 



Remarks. 



cut, 
204 

w| 

50] 

m 

20| 
30j 

t0 j 

50| 



cwt. 

4 

Hi 

15: 

23 



lb. 

L'SJ 
5 I'M 

7fio 
1000 



"fSASSL^^ ,e8ther - ' 



i' , l :;:;,;!.,, 1 "'^ ■»••' ■*, — , .„ ,„, 



. . . 



Kam comparatively new; packing i., place 
of cup leather. ° ' 



10.0 
7.7 

— — 

i.i 
7.1 

6.5 
6.7 



18.8 

11.1 

9." 
7.7 



Rested before and after renewal (1 f C up 
leathers. Those removed, however, were 
m good condition. 



Ditto. 



ditto. 



i 



This ram is used for .straightening juirj.os.-s 
as a hydraulic bear; it is fixed in a hori- 
zontal position. It was formerly fitted with 
cup leathers, but as these seldom lasted more 
than a week, the}' wen replaced by packing 
which has not been renewed for fcwel 

lnontlis. The Lear lias been in nai.stanl 
use night and day. 















1 -^ - - - S . 






' — - : ' — • 2 








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■peg -i.tAiJi 

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mag i|i-i.. ( | 






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{ 39fi ) 



Notes on Foundations. 






i 






TMIIE approximate safe load in tons per s.jnar.- foot is given in the following Table, and 
I_ will serve as a guide in preliminary designs. In foundations for important works 
it is recommended thai bores or trial pits be sunk, and the bearing capacity of the soil 
ascertained before starting the final designs. All tin- values given are for foundafci. 
.l.'j.tl.s Mow w.-uthrr influences, and no allowance has been made for the weight ol 
displaced soil, buoyancy, or the friction between the ground ami cylinders or caissons" 



Description >.f (imund. 



Approximate s 
Load in Tons 
per Square Foot. 



Bog, morass, quicksand, peat moss, marsh land - 

Mml, hard peat turf, silt ----.... 

>"it, wet, or muddy clays and alluvial deposits of moderate depth in 
river beds - 

Diluvial clay beds of rivers ---..__ 
Soft i-lay and we1 sand ---... 

Alluvial earth, loams, aud loamj soil (clay with 4<) to 70 per cent of 

sand) and clay Loams (clay with about :<0 per rent. ,,i sali ,i) 
< irdinary clay and dry sand mixed with clay - 
Loose sand in shifting river beds, fche safe load increasing with 

tin- depth - " 

Dry sand and dry clay - - - . . 

S.ltv sand of uniform and inn, character in a rive,- bed, secure from 

scour, and at depth greater than l'.j ft. 
Hard «lav iuix.-d with vcrv roarsesan.l - 

Sound yellow , lav, containing only the normal quantity of water '- 

Solid Mm clay, marl and rndurated marl, ami firm boulder gravel and 



: 



to | 



sand 



Soft chalk, impure and argillaceous - . 

Hard white chalk ..... ~ 

Ordinary superficial sand beds - - . ~ 

Firm sand in estuaries, bays etc 



i to 

to I 

1 


| t" 1'. 

2 


2£ to 3 


3 J to i 
l 
1 to 6 



5 to 8 

1 bo \l 

■2\ bo i 

t.', to 5 
6 

(i In s 

7 bo 9 



,.,..„ „ ,,2; 1 V ■ , " ,at ""' ■ rtU —* ,if -v) ■ '-■ «*«■ S 

., ::,;:,: est ] r A - " u - ""■ f u - - 1 "■•" ■ piera 

pressure due to , °"' y - ; ""' '"' ° f s '" h ;l " : "'"" *■* "- ■*»* 
1 the In, fa* doe8 ,„„ ,. x ,,. e ,, tlu , afe preagur( ^ ^^ 



< 



-* 
























«s* 



*r* b 






NOTES ON FOUNDATION'S. 



399 



The support afforded to cylinder or caisson foundation by surface friction will depend 
upon the nature oi the strata and the depth the cylinder or caisson has been sunk into the 



i»r nd. 




In practice 11 is nol usual bo r--lv upon friction as a supporting force, especially where 
the cylinders or caissons are increased in diameter at the bottom. 

The average frictions] resistance to drawing three hundred ordinary rough Memel timher 
piles, which had been driven into clay, was found to be about 16J cwt. p<-r square f. «ut 
of pile. 1 

The following Table gives the approximate surface friction that probably occurs 

in various i : — 



Approximate Surface 

Friction in Pounds 

jier Square Foot. 



Mud and silt on dry timher sawn piles 

Soft clay on timher sawn piles - - 

sharp sand "u clean timher sawn piles 

Fine soft drift Band do. «lo. - 

Mu« I ami silt on elean, emplaned cast iron 

Sandy mud «lo. do. 

Muddy clay do. do. 

Ordinary sand on unplaned cast iron - - _ - 

(Inn river-bed sand and gravel on unplaned cast iron 

Hard compact clay on unplaned cast iron 

< h'.liunn clay beds do. do. 

Silty fine Band,liquid when disturbed by water, on unplaned cast iron 

The clays above referred to are supposed to contain the normal quantity of water. 



100 to 


150 


160 to 


180 


1100 to 1500 


1500 to 1700 


50 to 


7i) 


150 to 


250 


250 to 


400 


300 to 


400 


400 to 


(100 


900 to 1000 


700 to 


.SOI. 


250 to 


300 



Concrete Foundations. 

rpilE necessary thickness of concrete Foundations that they may 
J distribute a loud \Y uniformly ovei the srarface A B may he 
found as above. 

Using the .-.one notation, we have 

d = 1.73 c s/jfc 

The ultimate tensile .resistance in a beam of g 1 cement or 

lias-lime concrete is about LOO lb. per square inch, and in a beam 
of g 1 brickwork ... cemenl as much sometimes as 3501b. per 

square inch. 

With a presaure U] the surface AB of, say 3 tons per qn 

foot, and a factor of safety of "-', 

d = 1.73 & 




r V*«.^ 



a 



■ t - 4- civil Eneineers," vol. l»v., pag® 313, 

1 "Minutes of Proceedings of the Institution of CivU nog 












* 







( 400 ) 



!: 



1 



I 




Timber Piles. 



Lei W = Safe load on pile in tons. 

P = Weight of hammer in tons. 

h = Distance of fiv.- fall of hammer in feet. 

8 = Penetration of pile for the las! blow in inch 



Thru 



W = 



■1 1 7, 



s+1 



This formula is suppos.-.l !,. ^ivea factor of safety of aboul 6. If a pile is driven 
with a hammer weighing a ton falling 20 ft. and causing a penetration, of I In, 

for the last blow, W would l»e 20 tons, which in ordinary practice is the usual lo 
allowed on piles well driven. 

Resistance of Piles in Sand. 

ME. J. SANMKMAX carried out a series of experiments to ascertain the resisfcanc< to 
horizontal stress of piles driven In different materials. The results showed that 
the greatest resistance was offered by sand, clay less, and loos, ashes the least. All the 
piles broke off about 5 ft. below the surface of the ground. These experiments are 
described in vol. xli. of the " Proceedings of the Institution of Civil Engineers." 



Weight of Timber Wet and Dry. 1 

T N imputing the weight of timber in caissons and similar work, it is necessarj 
A th. t r it should be calculated at its saturated weight. The following Table gi 
the weight of greenheaTt, elm, and oak when dry and after immersion in water: 



Weight |" i « 'ul.ic 

! 



GreenJieart Timber. 



\J hen <Irv - 
After 7 days in water - 
After 1 month in water 
After 2 months in watei 



When very dry - 

After 7 .lays in water - 
After 1 month in water 

Aftrr •_' months in water 



American Elm. 



When very dr\ - 
Aftrr 10 days in water 



Dantzic Oak 



lb. 




71 


12 


7:; 


5 


74 


11 


75 


5 


57 


." 


60 


11 


63 


12 


65 


10 



Pei © .:•' 
Iu< i ease in Wei 



2.18 

3.:» 7 

1.97 



39 
53 



6.22 
11.23 

1 l.-al 



:;:>.:• 



1 Compiled from "Notes on Construction in Mild Steel," bi 11. fidler. 



( 401 ) 



» » 



Timber. 

T11HK results of fche tests given in the following Tables are of special value, as they 
wviv obtained from experiments on large timbers, such as are generally used in 

practice. 

Transverse^ Compressive, awl Tensile Tests on Beams nj Y<-f!»w Pine} 



Span 
of 

1 V'.ini. 


Depth 

and 

Width. 


Weight 

per 

i tabic Fo< A 


Modulus 

(if 
Elasticity. 


Transverse 

Strength. 


* \ impressive 
Strength. 


Tensile 
Strength. 


ft. 


in. 


lbs. 


tons per square 
inch 


tuns per square 
inch 


tuns per square 
inch 


inns per square 
inch 


10 


6 x 12 


37 


412 


1.90 


1.18 


1.78 


10 


12 x 6 


36 


> ■ 


1.62 


1.06 


1.73 


u 


12 x 12 


40.6 


443 


1.82 


— 


— 


14 


9 x 9 


; 32.3 


395 


1.71 


— 


- 


14 


18 x 9 


31.6 


. . . 


1.57 







The result, given in the above Table are in all cases the average of three teste. 
The timber ased was Quebec yellow pine of good quality, which had been lying in • 

yard for five the after being purchased from the docks. It had not been seasoned, 

and when tested contained about as much moisture as most timber when actually ased. 
The baulks were sawn, and ... clearly show the fractures, all except those measuring 
12 in. by 12 in. were passed through the planing machine. 

Compressive Tests on Fir or Pine Timbers* 



Ratio of Length to Width. 



All Timbers 12 in. by 12 in. in section 



10 



og Weight in Compression : 
Tons per square foot of secti"i> 



1 21 ' 



15 



•j 1 1 25 



lis 



115 100 




45 50 



SO 7 « i •' 



. •• Notes on Docks 



For vam.ns methods of preserving timber, creosoting, etc., see 
id Dock Construction," by < • '■ <"1>""' M-b&E. 

> . • 

c /*- -l F.ncnneerfl vol. cxxviu., 
1 "Minutes of Proceedings of the Institution of Uvu b g 

page 334. 

" It>id., \ul. wix., page 66. 3 F 






( 402 ) 



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( 403 ) 






'VR 









Stability and 



F 



PS::, of **■** 



ar 



ln '' ' known load the r 

^ ** « *™: ss %~ ^j.^ l( t ,„. 



""'OH DlA6flAM 




L0A ° "WW* 0,4G«AM. 











**"°'«6 "OMEHT O/AGRAM 




tf#=J*f 



;i ' ^^loagifcudinaland 

, ;: ;,I r v '"" »b the depth 
[' flotation is unifonn ; but 

11 * » **W unsymmet, 

"<*% aboul one axia the 
de P& of flotation at either 
, ''" 1 °* tins axis ma> be 
obtained as follows:— 
J ' 1 " '"<"< downward force on pon- 
toon, including ife own weight. 
/ = length of pontoon = (a + / 
s - WMfch of pontoon. 
<* - Average depth of flotation. 

«« height per cubic foot of water. 
''*- De P fch of flotation at end nearer 
centre of gravity. 

7,1 " De Pthof flotation at end further 

from centre of gravity, 
i = sh.mrr distance from centre of 

gravitj to end of pontoon. 



■"Uteris i, Mcif Am 



Then tf= L = ^M 







And //, 



/ 



i'of 






CflW /o '' <**»«*** load W ai „„, 



?ery approximately. 

TJic centre of gravitj of the loads G 
should intersect the centre of gravity of 
the displaced miter. 

Poinb t as in figure. 



Wain 6 



\y., m 2o / '' 




< 



404 



LABILITY AND FLOTATION OF RECTANGULAR PONTOONS, 






Origin at < >. 



Left oi 0, 



Load intensity 



Right of 0- 



(a v ) + 



Shearing force 


^v 1 

a 2 


( 


V Wo 

(I - •'• ) 


Bending 

moment 




( 


w . 

2a 


Moment at « ». 






U> \\ M 


M 






If + 2 


Shear at 1 > - 






\\\ + W, 


Loadinten-ii j 
at n 






2 \Y, W, 

a r> 



i' w w< 



f a - x \ 

■■„ < " - ■■■ ) 






2 \Y 6 



3 



2 



Load intensity 






at A 



W 3 + W, 
W 4 



at B 



For a series of loads tin- above treatment may he applied separately to each and the 
algebraic sum taken. 



Shearing Strength of Mortar Joint. 



A 



10-cwt. cast-iron block was laid frog downwards on a bed of cement mortar 
( - l " 1 )j tfte mortar being spread on the top of a granite course. It was 

allowed to set for five days, and then the block v. 
slid horizontally by means of an hydraulic jack. The 
pressure required to destroy the adhesion of the mortar 
to the granite (which was the line of failure) was 
4 tons per square foot of bed, equal to 63 lb. per 
square inch. 



— 2 Vi 

WCwt C I BLock 

„£ .* ,V ■ + 






ipceswi 



Lodn ■' • 

Isatora 

v.: • 

Hoi •: ■ 
Mr. 

■ 











Strength of Brickwork. 

rilHE following values are compiled from experiments made in 1895 by the Science 
A Standing Committee of the Royal Institute of British Architects. 1 Piers were 
'""It. ol different varieties of brick, 6 ft. high by is in. s 4 uare. Two of each * • 
1,11111 '" Hme mortar and two in Portland cement mortar. The testa were made at 
the end of three months and six mouths after building. The brickwork was as nearly 



i « 



Report on Brickwork Tests," published by the Institute, 



,-. - 



i 






V 












STBBIfOTa of ru, 

°* BRICKWORK 

" l "' ssiM " '""<■ c w, ,., ,, . , ' 40.5 

' '■ ""•'""" «» »,< „, , '. '" ' Prti of Ti,a„„. ,,J hc J""* mortar 

° - P'"> "i ».k|„,i ,„,.,. ' '•" g»j> .tone |,„„, ' '"-' -■■...!, wmM and 

"'" '"'—'• ""■ M " e ''™'- had no fcJJ TSZfT* "^ 



D^-ription. 



London stocks - 
Gault 

Blue 8te ff««i (half brick) 
London etocks (whole) 

Red rubbere (whole) - 

"liter whole) 

n (half; . 









Area Crushed j» 

■Niuare Feet 

(Average). 

.261 
.258 
.130 
.125 

.272 

.140 

.337 

.165 

.253 

.134 



'. llM ' 1 ^ tad0O sto, k s W 



Mean Crushing 
toeijgth in i 
per SQTuae Foot, 

84.27 
182.2 
382.1 

701.1 

92.85 

46.94 

84.11 

5S.71 
192.2 
160.7 



, AI1 " , »'^ London stocks u-i..\i 



7''-.v/-, s ._ 



Description. 



Age b WTeeka 



''''"'// £un< Bri 



Crushing Strength 
") rons per Square 

Foot (Mean). 



rtquetti s. 



Portland C 
lpartast *«dard 8 ^te Iofc 



™ ^Briquettes. | 

cement bj rolume. 



,! ;,;: ;i ' » A* M „.,.,, in 



' 



building tin* 



4 

12 
24 
34 

4 
J 3. 7 
24 



24 



6.08 

8. 73 
15.72 
28. 1 9 

31.45 
48.52 
56.15 



29.00 




* 


















-^** 















40G STRENGTH OF BRICK WORK. 

TESTS OF BRICK PIERS. AVERAGE VALUES. 
1. Brick only. 



Name «>t Brick. 


Where r 


- im. 


1 ommenoemenl of 

Failure in Tona per 

Foot Superficial 


Total Failure in 

Tons pei Fool 

Superficial. 


Loiiil«>n stocks - 


Sitl ingbourne 


76.25 


84.27 


Gault 


Burham 


102.:; 


182.2 


Leicester red 


EllistowD 


* 


148.15 


382.1 


Staffordshire blue 


Rowley Reg 


j 


71.6 


701.0 


Fletton 


Fletton district near 








IVt^rbort mi-1l 


• • - 


220.85 


2. Brickwork i it Morfttr. 








Name <•! Brick. 


\\ here Fr< >m. 


B] tekwork in 
Weeks. 


Commencement oi Total Failure in 
Failure in Tons per Tun- per Fool 
Foot Superficial. Superficial. 


London stocks 


Sittingbourne - 


L82* 


lis 


1 0. 4 1 






43i 


7.49 


12.54 


Gault - 


Burham 


22! 

IS! 


11.25 
5.58 


IS 64 
21.92 






L3« 


9.40 


21.60 


Leicester red - 


Ellistown 


22! 

18i ; 


15.44 
15.65 


31.14 
JO 74 






43« 


14.11 


34.12 


Staffordshire blue - 


Rowley Regis - 


2 1 . 

19' 


28.14 
28.53 


45.36 
74.30 






442 

• 


19.49 


73.66 


Fletton - 


Fletton district 


21| 

2 2 1 

« 


24.08 
24.08 


114.34 

;;o.<;s 


3. Brickwork ft 


i Cement. 








London storks 


Sitl iiiljI loiirne- 


21 


10.28 


1 t.93 






1 5 2 

■ 


9.05 


16.96 


Gault - 


Burham - 


215 
204* 

• 


27.45 
12.09 


39.29 

17.79 






1 5 2 


18.72 


29.98 


Leicester red - 


Ellistown 




093* 

_ « - 


37.24 
22.82 


51.34 
58.45 






16 


2:5.1:5 


50.43 


Staffordshire blue - 


Rowley Regis 


2] 

22 r* 

t 


62.33 
31.6 


83.36 
72.80 






164 

< 


36.86 


82.48 


Fletton - 


fletton district 


21 ■ 

20i 


84.99 
43.88 


135.43 
56.25 



* Onlv in the case of those marked with an asterisk, a portion of the pier was tilled 

m with closers of London stocks, and the results are given here because fchej represenl 
probable conditions, 



Hold 



■ 









■M 






--_" 






m 



Adhesion in 

I \\ K (KM 

Square Lncb. 



U5 

"■ 

PS 
M 

'• 
•• 

2.10 

0.8] 

2.10 

0.88 

2.10 

2.10 

1.76 






( 407 ) 

Holding Power f Rnit 

M - --•-—,. ,v,.°; tS „, "^asonry. 

Diameter ^"wato^ 

>;.!!;;!;, r otssr "sattf ***i ^^r — - — 

' *—* HoT ** 

i§ in. a in r: -— ,,m,u:k - 

* in - ; ft. <; ; n c , . __ 



i) 
•• 
»s 
PI 

M 

• < 

PS 
PS 

•« 
» 

ss 



n 

pj 

I in. 
pi 

91 
M 
PJ 



V] 






3 ft 6 

PI 
PS 
PS 
Pi 

*' 

M 
»| 

PI 

" 
II 
PI 
SS 




Cement neat 



" 






11 



M 

11 



Sulphur 

I.ea.l 

1 'Jnent neat 



IP 
PI 



J';,"r»oji, 

16,000 

16,000 

10,000 

16,000 

16,000 

16,000 

31,000 

12,000 
31,000 

13,000 

31,noo 

31,000 
26,000 



Bolt l.roJce 



11 



11 






M 



PJ 

PI 

PJ 

PS 

PJ 

M 

P) 



2 weeks old 



3! 



* » 



» ' 



it 



Bolt drew out 

''"It broke 
' :, »lt drew out 
Bolt broke 




Bolt* /',',-■ ,1 ;„ / • 



Holt drew out and broke 



PS 

PS 
PS 
PS 

•• 

PS 
PS 

M 



1 fn. plain 

- ut plain 
2 in. screwed 

2 in. plain 

- m« screwed 



< temenl 



M 
PI 

PS 

>s 



20,0001b 

21,no(i 

34,000 

67,000 .; 

32,000 , 
50,000 .. 



Cement began to yield 



■- 



Stones split 

' { "lts began to yield 

Stones split 



13 days old 
pi 

I! 

M 

PS 



• » w' 



Scientific American," vol. bait 



Cement and Concrete. 

l "" 1 "" Con*** (J^onaper sq,u, fol ,t after about a year.) 



I -'""- oi Cement, 



Proportion of Lime or Cement to Sand and GraveL 



I to 6 



I to H 



'""v Urn,. 

*«• lime 
4be rthawlin, e 
PortI *nd cemenl 



I to in 



I to 12 



10.2 
11.4 
34.1 
100.7 



4.6 
11.1 
21.8 

70.4 



5.2 

11.6 

1 :». I 

53.5 



37.1 



1 (I 'I' 



""' Principles of Structural .Design."' Scott-Moneriefl: 












1 




• AiX 




&»' 



•-*y 



3- -v 



;- , ■ r^^-;--*% 




40* 



< KNfENT AND COXCKETE. 



Transreis" S&renyth of Concrete.* 







x. .. 



Portland 
* leraent. 



1 


1 


2 


1 


3 


1 


J 


1 


•"' 


1 


(i 


1 


— 


1 


8 


1 





1 


10 


1 


11 


1 


12 


1 



Composition. 



A-r in 
I >.i\ <. 



Sand. 



Aggregate. 



o 

1 

2 

:; 



2 

— 



1 

9 



1 
5 

5 

.") 

5 

•> 

I I 
6 

<; 

9 

8 

— 
i 



( Joke breeze 
< Irushed brick 
Shingle 

» 

n 

•• 

Broken stone, I ' 

Gravel 

Broken stone, 1 ! 

Shingle 



i 






t 

6 
139 
139 

13! I 

I.-.!' 

90 

tin 
90 

95 

95 



Modulus "t" 

Rupture 

in 

Pounds per 

Square Inch. 

672 

195 

330 

2 17 

159 

99 

174 

l :w; 

136 

142 
132 
I ( 15 



ft marks. 



A comparison of the 
results of these experi 
ments, especially Nos. 
7. 8, and 9, shout - thai 
not onlythe amount of 
cementitious material, 
hut the -i-:iiluating «>J' 
the sizes of the aggi 
iMt.-. s<i as to till the 
interstices, is of im- 
portance. 



The following Table shows the quantity of Portland cement required to make 
1 cubic yard of concrete, cement weighing 1 cwt. per bushel:— 






.' u 



1* 



MkS 



.« 





Proportions. 


Cement. 






cwt. qrs. lbs. 




1 cement to 1 ballast. 


1 3 




1 9 


8 2 


Cement. 


1 » 3 j> 


6 2 


1 1 bags= 1 ton. 
1 1»m- =203 11.. 


5 
1 6 » 


5 1 
4 1 
3 3 




I T 


3 1 




1 » 8 „ 


3 




J 


2 2 14 




1 „ io „ 


2 2 



Fur 6 to 1 Portland 
Cement Concrete 

1 cul.ic foot = 136 lb. 

1 „ yard = L.64 tons. 

16 j „ feet = 1 ton. 

2 bags for 1 cubic yard of con- 
crete = 3 cwts. 2 qrs. 14 11», 



; a i T1 ?" mn T^ t "" >il< ' resi8tance ™ ll ***** of good cement or lias lime concrete 
is about 100 lb. per square inch. 8 



"The Principles of Structural Design." Scott-Moncrieff. 

«ak«T, "Lateral Pressure of Earthwork." (M.P.IGE., vol. Ixv.) 



loot to 



11 

\ an 

t*ft 



TV 






«v 






I 1 


















" 



( 400 ) 

STRENGTH OF CONCRETE. 

Tin- following results in Table I. are from experiments on Portland cement concrete 

CUDes i, v y\ v (,. !•'. Deacon in the construction of the Vyrnwy Dam. The second 

Table is riven by Trautwine for Portland cement concrete The third series of results are 

m the "Minutes of Proceedings of the Institution of Civil Engineers," vol. xxv., but 

the valnes there given are reduced to tons per square foot. ^^^^^ 



Table Number. 



I imposition. 



Age "i Block in 
Months. 



I 



1 

2 
17 
28J 
32" 



2 



25 J 
29] 
36 



i !i ashing Strength in 

Tons per 

Square root. 



Over 114 
102 
L59 
162 
1 80 






'-' 



1 to 5 



1 
3 
6 
9 
L2 



15 


mean) 


40 


n 




.;:, 


i) 




8--) 


>> 




100 







3 



Number of Month- Made, 



Three. 



Six. 



Nine. 



Meat Portland cement 
1 cemenl bo 1 sand 

I M 2 

I .. 

I .. . 

I .. 5 



- 



n 



2 ! I 

160 

129 

92 

86 

62 



343 

223 

177 

1 39 

115 

99 



385 
293 
235 
154 
142 



— .v. i sm -..i.* =s= ■==■ ;";;, ";;„;;t; g ^ .-. 

The , I to be used with Portland ' '^'^or mixing, the on"** being 

tree fr,.m earth] Bubsta «. Cold water -l"""' 1 "' • ^, mortar . Sail water is 

just i,-i.,,i .^ ™»« ii to become of the consisted ' ^^ ^ ^ ,-,„. which 

[uallj ■ a 1 •" "'-''• ' "I' 1 '''"' """"'" , ' i„l„.ntl ,ment has commenced 

Portland cemenl ie need -I Id be Brel well wetted, and ^ ^^ whell t „. 

t the proeeM should never be disturbed, as it ^^ u ^ kept und e, 

work Be, it will tap bj being tamereed m _ ^ rf ^ 1 ,„ 1 ,i al „i 

water ar rtronger I , th exposed to the «^J ,„„,, lli;l .l.- a tew p • - 

cemenl at pd n> rtrength to blue b**«*V Slall ,, : ,,i- gpecificatmn for 

The , teal LuaUty. etc, are given m ^^ g^ted with hot pitch uA 

Portland Cement Biti n concrete, oi dried c 

oil, weighs only 89 lb. per cubic foot. 3G 



&. 












■■ H 




4 in 



CEMENT AND CONCRETE 



Lime Mortar. 



i 



] 







Crushing Strength of Lime Mortar 
is Months old. 



Descript ion of Mortar. 



I 'rushing 

Strength in 

Tons per 

Square Foot. 



Lime mortar and viwv sand 
Linn* niMi't;ir and pit -and 

Mortar made with pounded 
sandstone 



98 i 



37.2 



26.8 



tensile Strength of Lime Mortal 



I description of Mortar 



Mortal of sand and hydraulic 

Lime, well made 
M' >Mar of sand and ordinary 

hydraulic lime, well made 
Mortar of sand and ordinary 

lime, well made 



Pensile 

Sta i jth in 

Ton- |m 
S«|uaiv I'M-.t. 



8.74 
5.46 
3,28 



The safe working stress in compression on ordinary lime mortar Is I tons per 
square foot, and the average weighl is 112 lb. per cubic foot 

Tensile Stress Required to Separate Bricks. Gem»,,t,d hither in Blocks of Four with 
PoTtland nt and Lirm Mortar. At th$ end of Twelve Months . „// >w tn Air. 







Tensile Stress in Cons per Square Ii 


ich. 






Area nf 
Bed 










Blue Lias 












Lime 


Description oi Brick. 


Separated 




Portland ( email and Sand. 




and Sand. 




in Square 
1 riches. 
























^^^HV_ 




Neat. 


1 to 1. 


2 to 1. 


3 to l. 


4 to 1. 


5 to l. 


1 to£ 


< raulty clay, pressed 


36.1 


11.3 


11 


6 


6.9 


5.1 




ID 


» wire cut - 

perforated 
Suffolk 

S topic 


37.0 
39.4 
40.5 


17 

27.1 

22.8 


t0.8 
20.7 
16.3 


■ * a 

15.5 

1 0.0 


7.2 
1 1.6 
14.1 


5.5 

7.5 
L3.4 


5.4 
5.6 
9.3 


1 n .» 

I mimmd 

16.5 


• lock 0fM 


L9.6 


1 5.7 


10.9 


10.") 


5.7 


5.-'. 


8 9 


rarenam re»l 

Staffordshire blue, | 

pressed with frog | 

Staffordshire Line, l 


36.1 


31.5 


20.8 


1 t.3 


1 0. 1 


8.6 


7.2 


13.3 


36.1 


L7.8 


U 


12.3 


L0.7 


8.2 


5.2 


1 7.(5 


u ■ 1 
















rough, without frog 


36. 1 


12.1 


11.8 


12.1 


9.0 


6.9 


■ 


8.8 



















I 



Durability of Iron in Water. 



,„,,, lt - „ , , . ' , ""' ,,J nit* iron, and to some extent on the 

,;"'";' * fforded ] - •"■»■•■■«• growths covering the surface. The portion* liable 

^.^^^^^wilt^wrt^^ The available 
h m^e dnrabl 1^ ""^ , "" th " -'■" , "" 1 ex P^ence Is thai u, , iron 

less durdi'V.' "' U; ' 1 " 1 ' ,lla " cast iron < i "" 1 l1 "' opposite in rroafa water. - Bel is 

le>s durable than either in salt or fresh water. 



Weigh 

m 

a*7tf"> '" 
IV 



1 -vy 



• 









eu-a 






'u:\ 



i I 



% 



N 






plat. 







( 411 ) 






:c 






Weight of Kentiledge for Counterweight. 

rnill. sto • capacity of various materiala used for counterweight or ballast in 
1 swing bridges, cranes, caissons, etc, is required to estimate the «liniensions of 
the ballasl chamber or box. In swing bridges where timber decking is used, the 
saturated weight of 1 1 1 • - timber from ruin or snow should he taken in estimating 
ilir amount of counterweight necessary. In all cases an excess allowance of not less 
than 1" per cent, should lie made in the capacity of the hallast hox to allow a margin 
for adjustments and variations. 

The following Table has been compiled from various sources to show the stowage 
value of different materials: — 



« 









» • 






ftr.: 

at 



Item. 



1 




7 



9 



lo 



Cemenl concrete, composed of 4 parts of 
gravel, 1 of Portland cement, and 2 of 

sand. 

i Joncrete formed of nickel slag broken small, 
, ,,, hilly packed, rammed in layers oi 
about 1 tt. and grouted up solid with 
mortar composed of 1 part of Portland 
cement and 2 parte of sand. 

Rough broken cast iron in pieces easily 
handled, carefully packed in ballast box 
of Bwing bridge 

Rough pig iron, aboul 3 ft. 6 in. in length 
, lMl | of ordinary section, 4J in- ! »y I in,, 
laid in rows in alternate directions, and 
stowed as dose as possible. 

The same pigs broken in short lengths ol 
12 in. and under, laid in rows in alter- 
nate directions, and Btowed as close as 

possible. 
Steel i.uii. •hiu-> (hurra) alone 
Same as No. 5, the interstices being filled up 

with steel bun 

Steel burrs grouted with Portland cemen 
mortar j 1 of cement to 1 of sand and 
rammed (bun concrete). 

Cast ir-.n i,, blocks generally about .» in. 
long bj •"'• in. square with shaped pieces oi 
varying size, specially packed in a Boating 
ship caisson and grouted up with cement 

mortar. . f 

Specially cast slabs to Bt over stiffenera oi 

plate girder for counterweight. 



Weighl per 

( lublC Knot 

iii Pounds. 



L35.0 



167.0 



269.0 



284.05 



287.22 



303.0 
333.88 

350." 



365.0 



too 



Cubic Fi 
per 
l on. 



16.6 



13.42 



8.33 



.88 



7.79 



7.39 

6.71 

6.40 



6.14 



5.6 



Percentage 

of 
Intersl ices. 



Solid. 



Solid. 



10 



37 



36 



38 
27 

Practically 

solid. 

Practically 
solid. 



11 







7 V 



V>* 



2T 
















( 412 ) 

Aggregates in Concrete in Contact 

with Steel or Iron. 

IN the widening of Blackfriars Bridge, London, the hoop Iron bonding in the old 
abutments whirl, were built forty years ago was laid bare. The abutment 
I" ft. thick, built of stock brickwork in cement mortal with a granite fat irk. The 
hoop iron in all parts of tin* abutment* both above and below high water, was badly 
corroded. The hoop iron, mortar, and brick were analysed. When the faces of I 

sk bricks were examined and the surface dissolved in distilled water, the; 
0.166 per cent, of sulphuric anhydrides and 0.C095 per cent, of chlorides A 
of the hearting brick in contact with a corroded iron tie when extracted with distilled 
wafcer gave 0-61 per cent, of sulphuric anhydrides and 0.005 per cent of chlorides 
Tip- .-■..rro.lr.l liuu,, imn removed from the brickwork gave L.72 per cent, of sulphiu 
anhydrides and 0.06 pel cent, of chlorides, both soluble in distilled water. The action 
"' ;,r " 1 dwwed that only 1.7 per cent, of metallic iron was left ... the corroded material. 
Eheae analyses showed (1) thai both the stock and hearting bricks contained sal 
whlch "'"■ " ,1 " 1 ' 1 " '" wai'T. H-Jtal.ly among them being sulpl.ai- and a small proportion 
"' chlorides; (2) that corrosion was almost complete in the hoop iron, and thai acid 
radicles corresponding to those found in the bricks also occur ... the iron; (3) that 
l1 "' formation of the iron salts was probaM.v ,1...- i,, the action of the salts present 
//«' bricks, and that in ferro-concrete construction the steel should be properlj coated 
with cement and attention given to the aggregates used in the concrete. 



Superimposed Loads on Floors 

of Buildings. 

rnilH actual loads on the floors of thr ffice buildings ... Boston were inves fced 

r- »1 f essrs ' Blackal] ; "" 1 Everett. The greatest number of ] pie known to be 

111 each office at any one time, ... addition to the weight of furniture and the contents, 
were included in the loads. The greatest load in any office w^ f..u„,l t„ 1., I. ..-J 11, 
I."' 1 SqU T are l "" t - The a™** average for all offices was found to be 17 It, per square 
oot. In 12.4 per cent, of the offices the floor load was in excess of 25 lb. per 
f00t ' : U " 1 '" ,- ,; P ei '•'•'"• jt needed 20 11, per square foot. Mr. C. G Schneider 
mves ^gated the average floor loads in office buildings, and submitted his invests mi 
^ a ^ a P er to the American Society of Civil Engineers in 1904. Eis investigations show. 

rtf°? b6amS ^" ,,M be desi S ned t0 carry concentrated loads occupying any posits 
^ u ^ e ^^ ^ ^U as distributed load in , of the av,,„, ,1,,!, i,',,l He cifc 

** ft^wing examples of heavy local loading: In an engineering office a aumb. oi 

™** • drawera h ^ **™® -,.,,. ,,!„,,.,, in a ,,„„,;,,. back ,, ,,,. k ni t] 

7'''';: •' 1 ';; 11 '- leases *ere 31 in. wide and 36 in. high, weighing when com- 
! y ": ' 1M,,K - '"" 1 "- i ^ or both together 320 lb per lirfeal foot, wil 
"I ;•';,;", A "»**»*«■ for drawings 31 in. by U in. and 5ft hi 

\:^ M ; ? "V"" M wei S h 1200 lb., or 326 II, per lineal foot. The weight a 
n,1 " k " ' kcase about H * high was found to be 170 lb. per lineal foot when 



« tir 

^0t - ' 






> 



am 






lad 






:, ;., 









. 






m 



Uaa 






irs 



^ 
•< 

M'** 

.#<* 






r£S 






SUPERIMPOSED LOADS ON FLOORS OF BUILDINGS. 



413 



completely filled with 1 ka \ torn of these bookcases may be placed each side of 

i partition, and woald therefore weigh 340 Ik per lineal foot in addition to the weighl 
f the partition. Movable partitions may b< ..-um.-.l to weigh about 14 lb. per square 
foot. Any of these loads may run parallel to or across the floor beams. The weights 
of safes i try from about 10 cwfc, upwards, and may be accepted as a minimum con- 
mtrated load. As special provision is made for the heavy safes, it is only necessary 
to considei the lighter ones as a movable load. The following live loads shall be 
assumed for the different classes of buildings and the maximum result used for deter- 
mining the sections :— 

(it), A uniform h»ad per square foot of floor area ; 
or (b\ A concentrated load, occupying an area of 5 ft. by 5 ft., applied to 

any part of the floor ; 
or (c). A uniform load per Lineal foot for the floor beams. 

TAve Loads. 



A. 



B. 



< ilaea i -r Buildi 



Average 

Uniform 

Load per 
Square Foot. 



cwts. 



Domestic dwellings, dormitories, in- 
firmaries, and hospitals - 
I 'ffice buildings : Upper Boors 
ho. First floors 

Do. Showrooms, ground 

floor, stairs, and 
, . , n ido 
Schoolrooms and theal res - 
Public halls, assembly rooms, and drill 

halls - - - - - 
I ictories with light machine tools, 
ordinary si stables, and coach 

and motor houses - 
Warehouses and fact* iries* - - I 
Power stations 1 uncovered floor ' 

< !ell rooms for electric Btations* 
Charging floow Eor foundries* 
Pavements in fronl of buildings - 
Can through buildings - 

E la1 roofs - 

I >o. used for storage 



3 

1 

■i 



( loncentrated 
Load. 



C. 



I 



'1 

u 

1! 



cwts. 

10 
20 

20 



Load per 

Lineal Foot 

of Girder. 



Not less than 



1 

from 2 

.. 1 
3 
2 
3 



25 

20 

30 



50 

from 50 



»i 



i 



n 

*■ 

M 



60 
60 

40 

80 

in 



cwts. 

.') 

5 
U 



10 
10 

10 



Proportion 

oi Depth 
of Beam to 

Span. 



10 
from 15 



Not less than for uppei 



ir. 

20 

15 

15 

5 

floors 






1 

l 

i 



l 

■j n 

i 

20 



A 



h 



i 

i 
1 5 

V 

1 .*• 
I 

1 3 
1 

3 ;. 

1 




■^«^«ttJM 



Note. I. the local bye-laws specify a m "»" '"•" , tll( .',, ise f those inarfcea 
uet be token instead of the loads under Column a. weight ((f ,„,.. 

ith an asterisk, the actual loads are to be pertained, i ^ and ;m ordinary 

proof tl ji.i.sti-.i.-tjon i< i" be taken at oo o. i ^ rf of fc e flooring. 

timber floor ai 281b. per square foot, in addition to Ui su 



Inn- 
with 

I"' 




*> 



1 




. ^H* 







f 414 ) 









0> 

c 

o 

E 

o 



.2 
v 






0) 

a 
o 

Q. 



R 2 o g 



■- -T 

Sir 



° " - 
i K 



- / 

- /. 



c 



v 

> 

y; 

= 



- 



X 

58 



- ■ — 

- - 

S3 - 



r. 






X r- "2 



•- 



i- C — 



1- 



-t 
*7 



— 



K 



-A 



'_ ' — 



£5 



7 

3 



S 






^_ i 



o 3 <- 



- z: / 



- 



id -r ti 



- 



ti -t r: 



_ 7i" 

71 — 



- Q0 



2 B 



?l 



ti ?i 



"^ ^ -* 






iC 



3 



ic — i-. 

«5 7i ?i 






I' IC - 



- 
-r 

- 

> 



W — X 

ic it r: 



x 



3 









7i 
71 



71 
71 



I - 



X 



71 



I* C 



° '-t l~ 



z *~ 



2 ? S 



i- £ 



■ - 



- 






IC 



tJ 



?1 



71 £ 

: i — 



if* i* 

- *. ' -. ' ■ 



• - 
- i- 






7» iq q - 

71 ?i H -". 



if :f 



L 



< <! 



- 



71 



< 



: 

— 
- 



< 



:i 7i 



•^ •• 



?i - — 



S *tr "^ 

't 'f cc 



•H 30 Eg 

t '7 :: 







- 












SJ 






:■ 


















— 






-r 


• » 


- ' 


sj 









1 




»C 


- M 


i' 


— 
- 






- 












> 






-^ 












< 


















— 


















- — 




















- * 


I- 


03 


2 


-T 


71 


— 


:i 


- 


t 


7J 


jn 


t 


:: 


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-* 





■ I I 



1 ' t — I 



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— 

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1/ B? 



.T rr 



t • 






~ a 






i a "2 ** * .2 •£! -= t 

^: " v *g 5 W ■< — /i fc. 

- - ^ = •' 

- » o Q ^ - 






S - S £ >l a 



•-■ fj 



• r 















■- 



^ 






- : ■ 
* tea 



?i 



::•!?: 


















• 



- 

- 



• - 






: • 
- 



- 



- - 






• 



j 









( 41« ) 



Weights of Materials and Merchandise 



Matei ial 



Titnbt /•>. 
Mahogany, Spanish - 
Honduras 
Plane - 
PoplaT 

„ Whlfr- 

20 per '••■ill. Water 

I inn Hark 

Black Butt 

Cedar - - 

I lypress - 

Maple 

Cherry - 

Sycamore, tin- 
Karri . 

Masonry^ Rock, etc. 
Rubble Masonry 

Mas.niiTjgoud rubl»lr in mortar, 
well dressed 

Masonry,g 1 rubble in mortar, 

«lr\ 

< -lanitc Masonry 
Sandstone Masonry - 
Brickwork - 
Lime Mortar -. 

har.leiir.l 
I'.rirk . 

< '--incut Concrete - 

< Joke Breeze Concrete 
Quick Lime - 
Portland Cement 

I rranite » 

Cornish 
,. Aberdeen 
Sandstone - 

Limestone, granular 
,, compacl 

Trap Rock, Basalt - 
Quartz 

Marble - 

< in. : • 3 

Slate - 

Coal, ordinary broken, loose 
„ anthracite 



Weighl |"i 
I tabic Fool 
in Pounds. 



53 •;•; 

35 

41 
25 

64 

56 

35 37 

:{7 
40 
42 
37 
63 



I 15 -1 H 

L54 

1 38 

160 

1 to 

112 

1(1!) 

L03 
125 
130—150 
89 
95 
81—102 
160—170 
1G6 

164 

130—157 
125 

168 

17(i L87 

165 
Mil 172 

168 
162—180 

56 

93.5 



Material 



1 oal, bituminous - 

broken, loose 
Coke - 

„ loose - 

Gypsum 

Mica 

Shales, red or black 

Earths, Sniis. etc. 
Karth, < \.uimon Loam, dry, 

loose - 

Earth, < lommon Loam, moist, 
loose - - - - 

Mud, ilrv - 

„ wet - 
fluid - 
Sand, - 1 r\ 

damp - 

< rravel - 
Shale - 
Chalk - 

.. .in- dried 
Clay 

Miscellaneous 
Water, 32 deg Fahr. - 

hi- - 

Snow, fresh fallen 

moistened and conipai U-i 

Asbestos 
White Lead - 
Pitch - 
Tar 

Asphalt 
Ballast- 
Cork - . 
Plate glass - 
Window glass 
Flint glass - 

< train, loose 

packed 
Tallow - - - 

Petroleum 

Salt - . 

Sulphur 



W ■ -Ml |„.-| 

1 bic I 
in Poum 

77 -90 
17 52 
10 50 
2:; 32 

142 

183 

162 



72-8d 

66 76 

80 -110 

110—130 

104 120 

90 

lis 

109 
162 
174 
1 55 
135 



62.4 

57 
5-12 
15- 50 
187 
197 

72 

62 63J 

8.s 

112 

15 

169 

L54- 157 

1-7 -:<^ 

i'.' 
:>i 
58 
55 

n 

1 25 



Nom— For additional weights, see page 41 1. 






mdise, 



'•> 



- . 















. 























Revis 

Por 







IXTRODUCTIOX, 



The following specifications embody the general practice of Sir William 
Arrol and Company, Limited in the design and manufacture of cranes, bridges 
workshop buildings, and general constructional steelwork. In their preparation 
the published specifications of British, Continental and American eii'dn.-.-rs 
have been consulted, and the specifications represent the best practice and 
principles in the design of first-class structures. The working stresses for 
railway bridge superstructures are based upon the specifications prepared by 
Sir Benjamin Baker for the Imperial Chinese Railways. 

Sound engineering judgment and experience must he used in the inter- 
pretation and application of these specifications to particular cases, and the 
right is reserved to make modifications to them to suit sp.eiried con- 
ditions and variations and improvements in current practice. 



oil. ' 

Bittl" 






*K 



v MdU 
■BBHT t r 

& 

■cfewt ai 
•~ raddc 

illc 



Hind 






DO , 



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Hi 



( 410 ) 



M U iaK 



nfOM 


\h;u\ lyKul. 




Work iii? 

Load-. 


1 






rest L ads. 




sure. 



Momentum, 
Impact, Etc, 



Revised Specification for the Structural 
Portion of Heavy Cantilever Cranes. 

1. Thr whole of bhe structural steelwork, unless otherwise distinctly <p«viii r .l 
shall 1»' of steel, conforming to the specification of bhe British Engineering Standards 
i omiuittee. It shall 1"- made by fche Siemens-Martin open-hearth aeid process, 
and have an ultimate tensile strength of from 28 to 32 tons per square inch; with an 
elongation of at least 20 per cent, in a length of 8 in. 

Rivet steel shall have :»n ultimate tensile strength of from "26 to 30 tons per square 
inch, and q minimum elongation of 25 per cent, in a length of 8 diameters. 

Steel for forgings shall have an ultimate tensile strength of from 28 to 32 tons per 
square inch, with a minimum elongation of 25 per cent, in a length of 8 diameters. 

Casl steel shaU be practically free from blowholes and other defects, and is to 
be annealed in all case-, and have an ultimate tensile strength of from 27 to 32 tons per 
squaiv inch, with an elongation of at least 13 pel cent, in a length of 6 in. 

2. The dead load shall he the whole of the structural steelwork, including all 
machinery, ropes and counterweight. 

3. The working loads shall be the maximum loads specified to be lifted at the 
different radii. To the moving loads the weights of the jenny, ropes and slim: 
sh.ll be added in computing the maximum stresses. 

t. Th, cranes shall 1,,- i,sted with Loads, 20 pel cent in excess of the working loads at 
theii specified radii, and shall be put through all the motions. 

5 The wind pressure shall be taken al 50 lb. per square foot when the crane is lifting 

,,., 1 . and at 5 lb. per . fool when the crene ,- lifting the loads causing the max - 

,. When the crane is lifting the teat loads -1 pressure shaU t* mm d. 

I he I pressure shall be assumed to act on a «*»«£,' 

., - the area of the surface seen in elevation, except when a surface shelters 

portions behind it. 

6. The various stresses caused by the hoisting of ^V^Tv '^1?!^ 

-! I, and .1 ffeci of brakes -hall be considered m proport. D 

areas of different parts of the structure. following additions 

In no case shall these stresses he assumed to be less 

to the direct atatic stresses:— including slings and ropes, 

Lifting to L fr.-2j pe, at. of the load ^ «« te * ^ch increase 

for all ; up to 5 ft. per minute, and increased b) i 

of 5 ft. per minute. t . (lf t j, e total moving weight 

Slewing I Stopping the I Ud /A-l r^Vtl, . rack . 

fox speeds up to 20 ft. per miniit«* at tin- pitch eirc e o ^ ^^ ^ m i u ute. 

tiacMng.-2 per cent, of the moving weight, for speew 

Brakes.— 2!, per cent, of the load being lifted. 



A 







■» «. • » ■■ *■ 



4-20 



HEAVY CANTILEVER CRANES. 



Maximum 

I'nit Stresses 

in Tension 
and Com* 
pression. 



Alternating 

Stresses. 



Shearing, 

Bearing and 

Bending 

Stresses. 



Rollers. 



J >int- in 

Members. 



7. In no case shall the combined stresses under working conditions, wind <>r i 
loads, exceed three-tenths of the minimum ultimate strength of the material, nor shall 
they be more than the following: — 

Under Dead Load, Working Loads-, Impact and 5 lb. Wind. -The maximum 
-tress shall not exceed 6| tons per square inch "ii the nel section in tension or com- 
pression, but in no case shall the member in compression be subjected to a 
loud than one-lifth of its ultimate strength when considered as a column. 

Under Dead Load an I 50/6. Wuid. — The maximum sties- shall not exceed 7 \ tuns per 
square inch on the net section in tin-ion or compression, but in no case shall the member 
in compression l.e subjected to a greater stress than one-fourth of its ultimate strength 
when (•uiisidi'i-rd as a column, 

S. Mdahfrs suhjeeted t<> alternate tension ami ec mi j >i-. --j, .n -hall be proportioned as 
a strut to resist the greater stress added to one-half of the lesser stress, except in the case 

of wind bracing, where the member shall be proportioned t -i-t the greater stress. The 

suni of the stresses shall be used in designing the connections. 

9. The shearing, hearing and Lending stresses per square inch shall not exceed 
the following limits : — 

(1) In Truss or Lattice Girders, and Web or Flange Joints of Plate Girders — 

[a) For machine-driven rivets, or turned bolts and pins of a -hiving lit 

Shearing stress ... J of tin- permissible tensile stress. 
Bearing stress ... \\ do. do. 

Bending stress .. U do. do. 

(b) Fur hand-driven rivets over 1 diameter- i,, length. The number found by 

(a) -hall he increased by 10 per cunt. 

(2) In Plate Girders— 

Shearing stress in rivets ... £ of the permissible tensile stress in the girder. 

Shearing stress in web plates... I do. do. do. 

Bearing stress on rivets ... 1J do. do. do. 

(3) Bending Stress on Members Subject to Direct Tensile or Compressive Str< - 
Where such stresses occur the member shall be proportioned t«. the algebraic sum of 
the stresses resulting from the direct stresses and three-fourths of the maximum bendu 
stress, and the stress per square inch shall not exceed that permitted for the direi 
stresses. The member shall be considered as a beam freely supported at the cud-, and the 
bending moment at the ends shall be assumed to be equal to that in the centre, but 
in the opposite direction. 

10. The pressure in pounds per lineal inch of the live rollers of cast or rolled steel 
shall not exceed MOOrf, when- d is the mean diameter in inches. 

11. All joints shall be fully covered and riveted to transmit the maximum str< 

M : ' ; l "'" i "~ stress through the rivets, except in the case of the tower lege which are 
machined, after each section is riveted, so as to bear throughout their whole faces, in 
which ea-e they shall he covered and riveted to transmit at least one-third of the 
thrust as a shearing stress through the rivets. The cover plates shall have a sectional 
area 2o per cent, in excess of the sections joined. 



***** 

dfam 

: 

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: 

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— I I »" 

7- 'in 
ilk roller 

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HKAVY OANTILRVKR CRANES. 



421 



* 



*H 



onal 

\ 






Foundations. 



Constructional 
Details. 









Workman 
ship, 









p nt in... 



-::r. 






* 



+ *** 



12. in estimating tin- actional areas of the flanges of the jib, the mils ™d ftoor 
plating shall nol be included in the area. Foi aet sections the diameter of the rivet 
holea shall be taken as \ in. larger than the nominal diameter of the rivet before 
driving for full-headed rivets, and \ in. for countersunk In -ads. 

In plate girders, one-eighth of the gross section of the web plate shall be included 
( n the sectional area of the Range, and the web covered to transmit horizontal 
si 

13. The pressure »>n the concn-ti- of the foundations shall not exceed 10 tons 

.„.,. 30 fool andei the working loads, dead load and wind pressure. 

14. All members shall be designed of such form as to be accessible for inspection 
^n, I painting, and to allow a free circulation of air through the member. 

T«. allow foi corrosive influences in the vicinity of manufacturing districts and 
neai the sea, no angle, plate or bar shall be used of a less thickness than '■■ in. 

To minimise viWations, and to provide a substantial and rigid frame, all members 
of the crane shall be formed of sections capable of resisting tension or compression, 
and the diagonal bracing of the town- shall be designed as tension members only. 

The diameter of the roller-path shall be such that, under all conditions of loading, 
the centre of gravity of the loaded or unloaded jib shall not approach nearer the centre 
of the roller-path than one-tenth of the diameter. 

\11 radial bars and roller frame of the live ring shall be formed of rigid members, 
with suitable tangential bare to maintain the relative .notion of the parts oi the frame. 

To provid e for emergency loading and a construction of a substantial and durable 
character the centre pin, with the girders carrying it and ^™^*?£ 
desig 1 to resist a vortical and horizontal force of at least two-thuds of the maximum 

load lifted by the crane. . . - t , 

The size of the tower i„ plan shall be such that no tensron .hall «t m th, 

foundations. 

IS I .,. -hoi, of tl ,1 sl,i,, shell l f the highest class. *£»£*£ 

of all plate. I barn shall be pi ., or machined, and aUWes dnM. H*»uhe 

or, rrive mall I eed where p, icabla "/,":„ , s ,,,,„.,, a,„l 

pn „.i,,- of the tower shall be machined atte r the a* ' 

before fitting tl ver plates, so a. to enenre perfect contact on the abn. 

M »)t 'hole of the etrncturm eteelwor^^^ 

- «"' ' ^^Lei^necoetof, , 

(4) Where two surf - i ' «*« . , ;lfter „ reeli ,„, shall « ive 

»nd all parte which are not accessible to pamting a. 

two coat, of petal before being riveted togetoer ^ ^ 

(.) After erecti t site, the whole .hall receive at least one fimehing 

beei oxide paint of an approved colour. ^ , ml 

0) All bright parte shall 1 ated with a smtable nnxtur 

tallow. 







•: 























( 422 ) 






Materials. 



I »'';i'l Load 



Working 
Loads, 



Test Loads, 



Permissible 
Working 
Stresses in 
Tension and 
I 'Ompressii m, 



General Specification for Structural 
Steelwork for Travelling Cranes. 

1. The whole <>f fche structural steelwork, unless othei wis.- distinctly specified shall 
be of steel, conforming to the specifications of the British Engineering Stands] 
Committee. It shall be made by the Siemens-Martin open-hearth acid pi .-. and 
have an ultimate tensile strength of from 28 to 32 tons per square inch, with an 
elongation of at least 20 per cent, in a 1. ngth of S in. 

Rivet steel shall have an ultimate tensile strength of from 26 to 30 tons per squa 
inch, and a minimum elongation of 25 per cent, in a Length of 8 diameters. 

Cast steel shall be practically free from blow-holes and other defects, and is to 
be annealed in all cases, and have an ultimate tensile strength of from 27 to 32 tons 
per square inch, with an elongation of .it least 1.3 per cent, in a length of 6 in. 

2. The dead Load shall he the whole of the structural steelwork, including all 
fixed machinery, shafting, motors and operators' cage. 

3. The working loads shall be the maximum loads specified t«» be lifted. In 
computing the maximum stresses, the weights of the crab, ropes and slings shall be 
added to the moving loads. 

4. The cranes shall he tested with loads 50 per cent, in excess of the working 
loads, and shall 1m- put through all their motions. 

5. Under the various forces to which the crane may he subjected from liftin 
and lowering the full load, starting and stopping the longitudinal and cross travel of 
crane at the specified speeds, and the effect of brakes, the stresses shall nol exceed 
the limits hereinafter specified. 

(a) Horizontal Chords of ike Main Girders and Carriage Girders. 

The sectional areas shall he proportioned so that the maximum -tress shall 
not exceed 6 tons per square inch on the net section, whether in tension or 
compression; nor shall the direct compressive stress per square inch on the 
gross section exceed the fraction (0.95 - 0.003 r) of this permissible stn .r 
he greater than S.a ,,,-r rent, of (i tons, (r is the ratio of the length of the 
unbraced portion to its h-as, radius of gyration.) 

(b) Diagonal Web Members of Lattice Mai,, (Orders. 

The sectional areas shall he proportioned so that the maxinn.ni stress shall 
not exceed the permissible stress on the net section for the diagonal next 
each end carriage, and 4.1 tons for the diagonal on each side of the cent] 
of the spa.., whether they are in tension or compression, and. for diag Is 
lying L-tween these points, the stress per square inch shall he reduced in a 
decreasing ratio from the higher limit at the end carriages to the lower limi; 
at the centre of the girder. The working stress so determined shall he called 



■ 



nil 

of 

ill 



da 

It 

of 

Fhe 






tot The 

. 

Wtawlii 

awtbwi 

H for 

Jib. 

■;'• I 

IftiL 












•"■■'■.. 






R. 



¥* 



TRAVELLING CRANES. 



423 



tural 
ies. 



■ 







■m 



^ 



I* 






mating 



Combined 

i ml 



Joints in 
Members. 



S tiona] 



( 



-i. 



"the pennissible tensile stress." For diagonals subjected to compressive stress 
the sectional areas shall be proportioned so that the stress per square inch 
on the gross section shall not exceed the fraction (0.95 - 0.003 r) of the 
permissible tensile stress, nor he greater than 85 per cent, of this stress. 
(r is the ratio of the length of the unbraced portion to its least radius of 
gyration.) 

i Shearing Stress on Web Plates. 

The shearing stress per square inch on the gross section shall not exceed 
one-half of the permissible stress; and tin- web plates shall be suitably 
stiffened against buckling at intervals not exceeding 5 ft. where the thickness 
of the web plate is less than one-sixtieth of the unsupported depth, ami at 
all points of application of concentrated loads. 

(d) Rivets. 

The shearing stress per square inch on rivets in lattice girders shall not 
exceed three-quarters of the permissible tensile stress in the member, and the 
li.-urinu <tiv>> ••in* and one-half times the permissible tensile stress, and 
in plate girders Beven-eighths and one and three-quarters respectively. The 
diameter of the rivet shall be the diameter before driving, and the bearing 
area shall be the diameter of the rivet multiplied by the minimum thickness 
of the l»ar i»r plate in the connection. 

6 II,,. sectional areas of members subjected to alternate tension and compression 
B haU be proportioned as a -tint for the greater stress in the member added to one-half 
of the lesser stress. The sun, of the stresses shall be used in designing the connection. 

7. Members subjected to bending and direct stresses shall be proportioned so that 
the combined stress per square inch shall not exceed that allowed for the direct stress 
alone. The ,„.,„,„,, st ress shall be calculated by assuming a freely supported span 
of three^uarters of a panel length, and the rail to distribute the load over a length 






not exceeding 12 in. 



8. AM joint, shall b. fully covered to ta-* the .hole .tea '-••£*• 
stress through the rivet*. The cover, slu.ll have . section*] area of at lea,t -> P e 
cent, in excess of the sections joined. 

, hl wtimating the seeti.ua. a,, of mam girde* * ^^ffi 

shall aol be included in the estimated area; for net sections the .. ^ ^ ^^ 
boles shall be take,, as j in. larger than the ncimnal diam< Mive sectioml 

driving for full headed rivets and \ in. for w"*^^ ^ ^^ ^ ^ 
area ol tension members formed of angle, tee or enan «* ^ ^^ of ^ free 
leg shall be the net sectional area of the riveted eg a. < < ^ ^ ^ ^ ^ 
; where they an connected by cleats, so as to oe ruuy^ 

Whole sectional u.va may h«- taken after deducting in * fhe web plat© shall be included 
In plate girders, one-eighth of the gross section o horizontal stresses. 

in the sectkmS «. of die flange, and the web covered to transm ^ 



10. The L'ir- 



ir ,, rs ,,,„ he construetca with a «». of not le» than 1 n, . 



Length. 












424 



TRAVELLING CRANES. 



Minimum 
Sections. 



i !onstruc- 

timial 

I Jetails. 



^ orkm&n- 
ship. 



Painting. 



1 1 No section shall be used in the main ami carriage girders of a less thickness than 
,V; in., nor a smaller scantling than 3 in. by 3 in,, and in the auxiliary girders and 
secondary bracing the thickness shall not be less than J in., and the scantling smaller than 

2$ in. by -21 in. 

1l'. Where the main or auxiliary girders are made of lattice construction all memfo 
shall be formed of rigid members capable of resisting tension or compression. 

The main girders shall be rigidly secured to the end carriage girders by hn 
gussets of amp].- dimensions and strength to keep the whole frame square and free 
from distortion. 

The centres of wheels in the end carriages -lull be spaced so thai the crane will 
run true and not r,..><diiip|, and shall, preferably, be spaced so thai the centres are no! 
less than one-fifth of the -pan. No member in compression shall have a grea 
unsupported length than 100 times its leas! radius ,.f gyration or 45 times in i.. a >i 
width 

13. The whole of the workmanship shall be of a first-class character throughout, 

true to dimensions, and neatly finished. 

All built members or girders shall be straighi and out of wind, and when riveted the 
component parts shall lit closely. 

All sheared edges of plates or bars shall be planed or machined, and the butting ends 
of compression members shall be planed or faced to bear throughout their whole tare! 

The ends of all girders that butt or fit against other webs shall be finished true and 
square, so as to give a good bearing, and the end angles shall be Hush with the ends of 
\\eb plates. 

All holes shall be drilled except where the connection is made by bolts, in which case 
the holes may be punched and reamed parallel or drilled after the parts are brought 
together and the bolts turned to be a driving lit. 

Rivets must complete!) till the holes and have large cup heads, and be machine driven 
wherever practicable. Countersinking shall be neatly done. 

14. (a) The whole of the structural steelwork before having the shop shall be scraped 

clean, and receive one coat of the best red-lead paint or boiled linseed oil. 
(6) \\ here two surfaces are in contact, one of them shall receive one coat of paint, 

and all parts which are not ae, ,1... to painting after erection shall receivi 

two coats of paint before being riveted together. 
(<•) Aide, erection at site, the whole shall receive at least one finishing coat of the 

best oxide paint of an approved colour. 

{d) All bright parts shall be coated with a suitable- mixture of white lead and 
tallow. 



Ger 



Material > I 
fed 

I- 

fn&Irai • 






Rai 






UPbui 



■'■'..v.. 

HBwia 






^-dba 



! - 



( 425 ) 



General Specifications for Bridge 



Superstructures. 







CONTEXTS. 



.Stk< < n rai Details. I Page 4:: --» 

Types <>t Bridges 

Minimum v ions 

Riveting - 

Temporal tire 

Camber - 

Joints 

I landrails 

Trough Flooring 

Wind Bracing and ('ni-> Uracim 



1 
2 
3 

4 
5 
6 

— 

8 



Description* Seotion, 

Materials for Bridges. (Page 427.) 

I Seneral - 

Rolled Steel - 

I >t Steel - 

Iron ------ 

Wrought Iron - 

Timber ------ 

Painting- - 

Railway Bridges. 
Loading. (Page 428 ) 

Dead Load 

Live Load 

w ind Pressure - 

Moment u I Train - 

Centrifugal Fi 

Working Stri asi s. I Page 430.) 

Impact - 

Permissible Maximum Stressea- 
Tensile - s ' ressi 
Compressive Si reeses 
Lltei oal ing Si i esses 
tearing, Bearing and Bending SI i ■esses 

Boilers and Bedplates - 
- a in Wrought Iron 
R ind and • !en1 rifugal For* i 
1 'iiiiections - 



9 
10 

11 

L3 



U 
15 
L6 
17 
18 
L9 
20 
21 

_ — 

23 



r 



24 

25 
26 

•-'7 
28 

31 
32 



Description. Section 

General Dati pob Calculations. (Page434.) 

Effective Spans, Depths and Lengths - - 33 

Sectional Areas - - - • - ;;4 

Loads - :;: ' 

Riveting in Webs - :; '_' 

Cross Bracinff between Struts - ■ : '" 



Rolled I Beam Spans. (Page 4:15.) 

Depth --""" 
Construction with Open Fl«»»r - 
Construction with Plated Floor- 

( ieneral - 



. 38 

. 39 

- 4d 

- 41 



Plate Girdeb Spans. (Page436.) 

Depth - 

Splices - 

Flanges - 

Web Plates and Stiffeners 

Cross Bracing in Deck Spans - 

Lateral Bracing - 



- 42 

- 4:i 

- 4t 

. 45 

- 46 

- 47 



^vetbp Teuss on Lattice GmnBBS. (Page 4370 

General Design - * " ^ _ 4 ,, 

General Proportions - - " w 

Construction of Main Girders - gJ 

Construction of Floor Girders - 

HalpTheouob Beidoes. (Page438.j RQ 

< General - 



. M 



!,,,, K Bridges. (Page 438.) 



General - 



:.: I 



Wobemanshif. (Page 438.) ^ 

<;,iieial - ■ iTiitin" "f Sheared 

Kcl"t's . - 56 

P ';, 1 ;,n.min S .„ 1 ,,R i v*..g • B7 

|.', V il.ars - - OO 

Loop Ends to Bars - . . 59 

Screw Ends bo Bars • 3 x 


















420 

I k'scription. 
Workmanship -< bniinued. 

Riveted Tension Bars - 

Pins 

Rollers and Bedplates - 

Steel Trestles or Piers. 

Loading. (Page 439, 1 

Dead Load 
Live Load 

w bad Pressure - 

Momentum of Train and Centrifugal Force 

Temperaf ure 

Working Stresses. (Page 440.) 

Impact ----- 
Permissible Maximum Stresses- 
Shearing, Bearing and Bending stresses 



CONTENT*. 



Seol ion 

- 60 

- r.l 

- 62 



63 
64 
1 15 
66 

*i7 



68 
69 



(Page 440 .) 



General Design of Trestles. 

< oust met ion 

Stability- 

I tiagonal Bracing 

( !olumns- 

A Meliorate 

Joints - 



Swing Bridges. 

Structural Dktati>. fl*age 441.) 

Type 

Centre Bearing Tyne - 
Rim Bearing Type 
Drum Girder - 
Roller Paths - 
Hollers - 
Roller Frames - 
Centre Castings- 
Rack Segments - 
Racks and Gear 
End Lifts .... 



71' 

73 

71 

75 

76 



78 

7: ' 
.s.i 

81 

XL' 

s:; 
84 

s.i 

87 



Description. 

Structub ll Details — Cuntin>»<l. 

Turning Machinery 
Lubrication 
Working Stresses 

Road Bridges. 
Loading. < Page 443.) 

Dead Load 
Live Load 
Electric Trains - 
W ind Pressure - 

Momentum 
Centrifugal Force 

Working Stresses. (Page 445.) 

Impact - 

Permissible Unit Stress. 

Tensile Stresses 

• lompressive Stresses 

Alternating Stresses 

Shearing, Bearing and Lending Stresses 

Rollers and Bedplates - 

Wrought Ironwork 

Wind and Centrifugal For. 

< Ipening Bridges 

Connections 



Section 

- 88 

- 89 
90 



91 
92 
93 
94 

j »:, 

96 



'.'7 
98 
99 

l.HI 
I'll 

L02 

l.c: 

104 

I . IS 
Km; 

107 



Sriii<TfKAi Details (I'a-^e 447. > - 108 

Types of Bridge Flo.. us. (Page 447.) 

Timber Floors - - - - -109 
Solid Floors 110 

Steel Plate Floors - - - - 111 

Flat Plates 112 

Buckled Plates - - - - -113 

Curved Plates - - - - - 114 

Corrugated Plates - - - -116 

Minimum Thickness of Floor Plates 116 

Jack Arclu-s - - - 117 



iv«fc 

All**!' 

... •:- 

<ripot 

.• 

vt3t*0fl 

■ 






- 



iwlfr- 

- ':• :.■ '.', 

a P«mi 
k\ 



Minimi m CoNsTui . Tiox Gauoes for Road \nd Railway Brldqes. (Page 460.) 






R 






. 






I 






I 



I 



n 



■ I 

■ • 

■ 

■ « 



10 









RnUt^lStrrl. 



Rivet 5 



H 



1 'I ion 



( 427 ) 



Wrought Iron, 



Materials for Bridges. 

1. Tin* whole "i the structural hridgework, except bedplates, machinery and mining 
:i for swing bridges shall be "t' rolled steel. 

Xhe bedplates, machinery and turning gear shall generally he of cast steel or iron, or 

forged steel. 

Parapets and ornamental work may be of cast iron. 

All steel shall comply with the Specifications of the British Engineering Standards 
I immittee I r Structural Steel. 

2. All steel shall he made by the open-hearth acid process by approved manufacturers. 
It shall )>e free from laminations and surface defects. 

Stri] >t lengthwise or crosswise shall hare an ultimate tensile strength of not less 
than 28 tons and not more than :iJ tons per square inch of original section, with an 
elongation of not less than l'O per cent, in a Length of 8 in., and when heated uniformly 

„, : , !,] 1 red and cooled in water of so deg. Fahr., strips U in. wide must Maud 

ltt dmg double in , press to a curve of which the inner radius is 1 J times the thickness oi 

Steel for forging* -hall have an ultimate tensile strength of from 28 to 32 1 per 

square inch, with an elongation of a) least 25 per eent in 8 diameters. 

, ,. r ., _,.,., .,,,„ ,, av „ im „ lt „„„ e tensile strength of not less *«*»£ 

an,l no. , • than 30 tana per square inch of orig 1 sechon, with an elongation 

..f not less than 25 per cent in a leng I eight times the diameter. 

, steel casting shall be made of open-hearth steel -^^J** 

and practically n I blowholes. All castings shall beann al a ^ ^ 

an ultimate tensile rtrength of nol less than T, tons nor, - ■ - J J 

of original U «i. longatton of not less than 16 p. cent, in leng 

13 pes cent, in G in. 

«f«l nf such a strength that a 

6. All casting, shall I t the best tough gray "^ ^ ^^ without fracture 

bar 1 in. thick bj 2 in. deep placed upon bearings 3 t . apart* 

. weight of 2T cwt pUced at the centre wil leflection of not less | 

i;tv free from all defects, and 
6. («) When iron is used it shall he of a fibrous qnaht ^.^ ^ 

Bhall stand such forge tests a. shsJl prove the qumiq 

,,,,,1 i ta fitness for ths service. , iron sha il have an 

( 4) Bar. over 2 in. in diameter and angle « dot , .^ rf ^ 

dtet. tenmle strength of not less t « .2- -P ^^ of 8 h ,, 

section, will. B elongation of a. least 1-1 ^.y,,, to a curve of 

,„. ,. lUl . „f I,,....!!.* double when co tMteA 
which the inner radius is twice the th.chne sof t P ^ ^ 

(0) Plate b hall hav ultimate tens , e t . > ,.,,„, , s ,„ . ;; 

souue inch of original section, and an el mcll ani i 3 per 

at leas, B per cent, with the grain, and 1 


















& 



* 




a 










'I* 



r.1.,1 



x-r. 



Paintintr, 



I lead-Load. 



428 RAILWAY BRIDGES. 

cent, elongation across the grain. The cold bend shall he 35 deg. with the 
grain and 15 deg. across for J-in. plate, and proportionate amounts for 
other thicknesses, the radius of the curve heing equal to the thickness of 
the plate. 

(d) The wrought iron used for rivets, bolts and bars under 2 in. in diameter shall 
have an ultimate tensile strength of not less than 23 tons per square inch of 
original section, with an elongation of not less than 20 per cent, in 8 in., and 
shall bend double when cold without 'racking. 

7. All timber shall 1.,- ,.f the hest quality, sawn true and out of wind, full si/., and free 
from shakes, large or loose nuts, decayed wood, sap, worm holes, or any other defect which 
would impair its strength or durability. 

8. (a) The whole of the structural steelwork before leaving the shop shall be scraped 

clean, and receive one coal of the best red-lead paint or boiled linseed oil. 
(6) Where two surfaci s are in contact, one of them shall receive one coat of paint, 

and all parts which are not accessible to painting after erection shall receive 

two coats of paint before being riveted together, 
(c) After erection at site, the whole shall receive at least one finishing coat of best 

oxide paint nf an approved colour. 

{<!) All 1 .right [.arts shall he coated with a suitahle mixture of whit.- lead and 
tallow. 



Railway Bridges. 



Loading. 
9- The dead load must not be less than the actnaJ weight, and shall consist of 
the whole weight of the steel superstructure, permanent way and ballast, if any. The 
weight oi the ordinary permanent way, including 95 lb. rails, chairs, cms- sleepers, 

etc., shall be taken at U cwt. per lineal foot of single line ; ami for an open 11 

," MrlJl1 "' ,h " w '"" cross keepers, permanent way and guard rails, shalJ 

taken at 1 cwt. per lineal foot „f single line. When- ballast is used with ordinary 
l-nnan-,t way, the average depth shall h, taken at 12 in. and assumed to weigh 
1-0 lb. per square foot of floor. 

For spans of less than 200 ft. the total dead load shall be assumed to act at 
™ <»<*ed chord. For spans of 200 ft. and over, the total dead load will he I 
DriDuted at top and bottom chords as follows:— 

(1st.) On Loaded Chords: 

(a) One-half load resulting from weight of trusses. 

(6) Weight of horizontal wind bracing in plane of chords. 

(c) Weight of floor system, permanent way, etc. 

(d) One-half of load resulting from weight of cross bracing in the ease of a 

deck bridge. 

(2nd.) On Unloaded Chords: 

(a) One-half load resulting from weight of trusses. 













. yb* m 
***** 

fcri* 

IW&gtf 
Vtae v> 

I'M*'. 






■ 



t 



■ .ii ■ j 

V 

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nil, 






RAILWAY BRIDGES. 



429 






-•- • : 



1. e Ix*d' 






A A 



M 



lb) Weight "t horizontal wind bracing in plane of chords. 

(c) One-hall of load resulting from weight of cross bracing in the case .if a 
deck, or the whole of it in the case of a through bridge. 

10. The structure shall be designed to carry a moving Load for each track con- 
sisting of two engiro oupled, .it the head of a uniformly distributed train load. 

Tin- live-load Btressea will be the maximum stresses produced by the rolling load 
considered as b1 unman or as moving in either direction. In double-track structures 

track or both will be considered loaded, whichever may produce the greater 

Stresses. ' the trains will he supposed to move either in the same or in opposite 

directions. 

The diagram of train l".i.U shall he furnished with the inquiry and he shown 

upon the stress diagrams. 

Where no train Load ifi supplied with the inquiry, the live load per track of 
ndard 1 ft. 8J in. gauge shall be computed as follows:— 

For Main Gird* ra : 

Distributed rolling load per track - U tons per foot run + an excess rolling 
Load tO OCOUpy any position on the bridge at the same time equal to 



Wind l'i.->. 






,- ,.,„ s I KI,, JlL{^!Jll ) f i ni tnot greater than 25 tons. 



In 



For i ou Gird rs: 



10 - centre s of cross girde rsjnjeet\ 

5 i 



The load on each ems* girder from each track- 
Fur all C gildera up to 7 ft. centres - 19 tons. 

p or all cro8 s gibers beyond 7 ft eentres - U tons per foot run of rack 

plus BO ex<v.. load "f 10 tun- - ^ 

but not greater than LO tons. 

i r In either direction, horizontally, and to 
11. The wind 3hall be assumed acting in eithu airei , ^ ^ ^ ^ 

be blowing at a slight angle to the axis ; tf fteta dge so ^ 

:po8ed areas of the .1 •. and of 1 >oth windward «J^ ^ ^^ ^aceofthe 

the latt. temporarilj screened bya passing train. ^ ^ piesslirej 

leeward girder shall be included in the total ares M ^ ^' ice the ir depth, when 
except when the distance between the man. girders is mo 

the whol i -I area of leeward girder shall be taken. .^ xlUi „\ ^ b{? 56 [}) ])eT 

With do M « bhe bridge the wind V™*™™ m of eX posed surfacesof 

uiare foot, and with a train on the bndge al 30 . i ^ foot . and the cent re 

train ^ bridge. The train shall be taken at square r ^ ^ the train shall 

i pressure of taiin surface at 7J ft. shove rail level. >« ^ either condition 

be treated as a moving load. The maximum stresses 

to be taken ,n determining the necesaar] sectional areas - ^ w agguBeil t 

,,, providing the necessary anchorage for the "^^ 1Q cWt per Lineal foot : and 
he covered with a train of empt.v pas-.-i.ger carriage b ^ loade d. 
mil f a douhle-line hridge, the leeward track oxuj 



*> 



t 





• ,W 



7**.x 




r 



430 



RAILWAY BRIDGES, 






Momentum <»f 
Train. 



' 'enti ir'u_:.il 
F< nee. 



Impact. 



I Permissible 
Maximum 

Stresses. 



Tensile 

Stresses 



12. Special attention shall be given to the details of the structure to provide for the 
longitudinal stresses resulting from the tractive force of the engines or from the sudden 
application of continuous brakes to the train while on the bridge, and the horizontal force 
resulting from such action shall be taken as one-fifth of the weight of the train. 

13. When a bridge is on a curve, the resulting horizontal stresses due to the 
centrifugal action of the rolling load shall be provided for. 

The centrifugal force for each degree of curvature shall be assumed to be 1 pei cent 
of the maximum rolling load on all tracks for a speed of 30 miles per hour and undei and 
1 percent, shall be added for each increase in speed of 10 miles per hour. 

The centrifugal force shall be assumed to act a. 5 ft. above the level of the nils 
The radius in feet K shall be reduced to degrees in curvature D by the follow* 
i "lin nla : 1 ) = — . 

K 

In snmn.ting the resulting stresses, the wind shall be assumed to be acting in the 

same direction as the centrifugal force. 

Wokkixc; S j hi:- -is. 

14. The foUowing vyorking stresses have been proportioned to allow for dynamic 
actio., of the live load on lightly-loaded girders or members of girders ; 

15. All bridgework and trestle piers shall comply with the whole of the following 
conditions: — ° 

(1st.) The combined stresses, resulting fro,,, the rolling load, dead 1 1. wind 

" """," ■""' '■'•""•""-'1 force*, shall noi produce a greater tensile stre< 

than one-hall of the elastic limit, or equal ... three-tenths of the minimum 
ultimate tensile strength of the material, nor more than the corresponds 
compressive, shearing, bearing and bending stress,., as hereinafter set 

lorth ; l.ut 

(2nd.) The combined stresses, resulting from the rolling load and dead load alone, 
exclusive of wind, momentum and centrifugal force, shall not produce 
greater tensile stresses than those tabulated below. 



1(1. 



Far M„in Girders, Cross Girders and Rail Beareis oj Plate C truction. 



rnder i*(. ft. span 
20 ft. and under 25 ft. span.. 
25 ft. and under 30 ft. span 
•30 ft. and under 50 ft. span... 
50 ft. and under 80ft. span... 

For Truss and Lattice Girders. 
80ft. and under 160ft. span: 
Bottom chords ... 
Diagonals 
160ft. and under 200ft. span: 
Bottom chords ... 
Diagonals 



• ■ . 



- • . 



• - 



4! tons per square inch 
t| do. 

5 do. 

5| do. 

5i do. 



• ■ . 



5-| tons per square incl 
... 4 J to 5$ do. 



5f 

U to 5j 



do 
do 



u 



0* 



1 
1 



SpsctoLO. 

•r-x wok 

ikieristbei 

.TW:c; DOT 
■I 



time* i 

» strate, to i 
pi :•• to i 

lb. 









• h 






i:\ILWAY BRIDGES. 



431 



"' - • 



Alt' ! 



• * • 



• • 4 



... 6 to 7 tons per square inch 
... Ah to 7 do. 



:it»u 



S 

B . and 
& ading 

Stress's. 






300 ft. to 400 ft. span : 

Bottom chords ... 
Diagonals 

All span- : 

For wind-bracing 8J do. 

For floor suspenders ... ... ... 2£ do. 

Note. — The i{ tons stress on the diagonals will apply to those at the centre porta 
of the span and to the couuterbracing at the Bame point. The higher stresses will apply 

to those a1 the end portions of the span, -where the variations of stress are not so great. 
Intermediate diagonala will be Bubj«'«-t to stresses lyiny between the two limits. 

IT. For plate girders, the gross area of the compression flange shall not he less than 
that of the tension flange, nor shall the compressive stresses per square inch be more than 
v, per cent of the corresponding specified tensile stress. 

For truss or lattice girders, the compressive stress per square inch shall in the case of 

riveted members not <• id the fraction (0.95 - 0.003 r) of the corresponding specified 

tensile stress, nor in the case of pin-connected members the fraction (0.95 - 0.0045 r), 

where r is the ratio of the length of the unbraced portion of a member to its least radius of 

ration- dc* in anv case shall it exceed 85 per cent, of the said tensile stress. Xo 

.mpression member shall have a greater length than 100 times its least radius of gyration 

or 15 times its least width, except for wind-bracing, wind, may have , length not 

weeding 120 fames its leasl radius of gyration. 

18. Members subject to alternate tension and compression shall be proportioned 

to resist the greater stress added to one-half of the lesser stress, excep 

i„ the I t wind-bracing, where the member shall be proportioned to -,t the 

,,.„,. .,„_ ^ Bum of the stresses shall be used in designing the connections. 

19 . TlM . Bheaiillgi bearing and bending stresses per square inch shall not exceed 
the following limits :— 

, , | r» Ita* m CoUic Gibers, I aU M - M^. J** h H* **» 

«--— - **.t r £— — — i. - 

She*..* .toese ... * of ™£ re ^ h ^ tha giMer or member. 

ditto 
ditto 



Bearing Btresa 
Bending stres 



l.l 
1'. 



(6) For hand-driven rivets having a length ovei |four peters. 
1 7 The number found for (•) to be incra I by 10 per cent. 




(c) For ordinary black bolts. ner cent. 

The number found for («) to be ...creased 1, 25 per 



(2.) In Plate Girders. 

Shearing -trees in rivets 



Shearing stress in web plate 
Bearing stress on rivets 












Rollers and 
Bed] ilates. 



Wrought Iron- 
work. 



Wind aiifl 
< Centrifugal 
Force. 



Connections. 



Types of 
Bridges. 



Minimum Sec- 
tions. 



432 RAILWAY BRIDGES. 

(3.) Bendintj Stress on Members Subject to Direct Tensile or Compressive Stresses. 

Where such stresses occur tin- member shall be proportioned to the algebra 
sum of tin- -tresses resulting from the direct stresses and three-fourths of the 
maximum bending stress, and the stress per square inch shall not exceed 
that permitted t'«-r the direct stresses. The member shall be considered 
a beam freely supported at the ends, and the bending moment at the ends 
shall he considered equal to that in the centre but in opposite direction. 

20. The pressure in pounds per lineal inch on rollers of rolled steel shall not 
exceed 300 d, where 'I equals the diameter of the rollers in inches ; in the case oi 
live rollers under swing bridges the pressure shall not exceed three fourths of this am iunt. 

Bedplates and rockers shall I f sufficient area and strength to distribute the load 

oyer the masonry without exceeding a pressure of 16 tons per square foot for hard stone of 
20 ton.- per square foot for granite, and 10 tons per square foot for cement i-oiierete 
(4-2-1). 

21. Where wrought iron is used for any girder or member of a bridge, the worki 
stresses shall be 80 per cent, of those specified in the case of steel for members subject to 
tensile and bending stresses, and for short compression members; 85 per cent, for 
long compression members, and 90 per rent, for members subject to shearing and bearing 
stresses. 

22. Where the stresses resulting from the dead and live loads are combined with 
those due to the wind alone, or with the wind and centrifugal force, the preceding working 
stresses per square inch may be increased 25 per cent, but in no case shall they 

exceed three-tenths of the minimum ultimate tensile strength of the material. 

23. Connections shall be proportioned to develop the full strength of the member, 
notwithstanding that the calculated stress may be less. 

Note.— Where bridges or trestle piers have to he constructed to the requirements of 
the Hoard of Trade, the combined maximum stresses shall not exceed ■;■. tons per 
square inch in tension or compression in the ease of steel bridges, and 5 tons in the case of 
wrought-iron bridges; and the wind pressure shall be taken at 56 lb. per square foot 
of exposed surface on the loaded bridge and trestle. 

Structurax Details. 

24. For spans of 16 ft, and under, rolled beams may be used ; for spans from 16 ft. I 
80 ft, plate gilders shall 1... used : for spans from 80 ft. to 200 ft., riveted truss or lattii 
girders shall he used; and above 200 ft., either riveted or pin-connected truss or lattice 
girders may he used. 

25. No diape weighing less than (i lb. per lineal foot shall be used, nor any plate or 
bar less than ,*.. in. in thickness when both sides are accessible for painting, nor less than 
i in. when only one side is accessible for painting. Tin- web plate of plate girders shall 
not be less than J in. in thickness. The unsupported width of any plate subjected to COB 
pression shall not exceed thirty times its thickness, except in the case of flange plates of 
trough-shaped Looms and posts, where it may he forty times its thickness. No angle less 
'l.an 3 in. hy 2> in. shall be used in the main members of girders or trusses, or in any 



r j;i „f ik *1'1« 

. Tap** 
gkmetkBi 

ai»l « nJlf 
■ i* 

isalngikilu 

- 

s : <■■:■■ 



- 

- 

48 • vnui 
to*,. 



I 



1 ■- Fur 



i 

* «ealv i 







••• MLWAV feRIDGfcS. 



433 



member having rivets ; in. in .Hamster. No angle less than •_'[. in. by 2} in. shall be used 
in ;i nv pari of a bridge structure. 

End angli meeting tail bearers 01 eross-girderfi shall not be less in thickness than 
tin' thickness of the web plates. 

Bedplates shall not be less than j In. in thickness. 

V ban less than ] in, nor over 2 in. in thickness shall he used. The minimum 

>n shall be I in. b; in. The depth of eye bars for chords and main diagonals shall 
not be less than ,■, of the length of the horizontal projection of the distance between the 
points of support. 

No main pins shall be less than ■"■'. in. in diameter uot less than three-quarters of the 
width of the widest bar attached t" them. 

26. The pitch of rivets in tHe direction of the stress shall not exceed 8 in. in any case, 
more than sixteen times tin* thickness of the thiunesl outside plate or angle bar, nor 
be less than 3 diameters, and nol more than forty times the thickness of the thinni 
outside plate .it right angles to the stress The distance from tin- centre of the rivet or 
boh bole to the edge of a plate or bar shall not be less than L§ diameters in the case of 
machined or rolled edges, nor 1] diameters in the case of sheared edges, nor exceed eight 
times the thickness of the plate. 

At the ends of plate girder flange plates the pitch of rivets shall not exceed 
V. diameters for a Length sufficient to provide a number of rivets whose combined sectional 
treas shall be equal to the net sectional area of the flange plate. The flange plate shall be 
of such length that one-half of these rivets Bhall be beyond the theoretical end of the plate. 
Wl webs tie built up of two or more plates, the rivets, which are used solely for 
making the several thicknesses act as one plate, shall not be spaced more than 12 in. 
apart. Such coin] .und web plates shall not be used where the total thickness is less tlian 

'"'At the ends of riveted columns or struts for ■ length equal bo twice the widthof 
the member, the pitch of riveta shall not exceed \h diameters. 

> ,, .7. «••, lorn for expansion and traction due to change of temperature shall 

r "">" provided in all spans at the rate of 1 i... for every K'O it. m length. nll ,. , 

P Brid ^provided with suitable bearing plates riveted ^ ^ flan^ and b^l ed 

through tl bedplates to the masonry al ^rt}*'" 1 " 111 ";' 1 ^^' 












' ul«r. 



.1 



Olufa 



Th 

tie treme variations in length uuc ,u ; - -, -- - - d f fche n< 

the same time to prevent anj transverse motion or uphfting ot tne 

, ,. bfl cons tructed with a camber of 1 in. 
28, Bridges of ion ft. span and upward- snail ^ ^ fce obtame d 

ft. in length. With parallel chords H,,1, " ,, ) '' lintl((111 ,.,,„,! sections hy 

by making the top chord tions longer than the corresponding hotton 

j in. foi ever} in ft. of length. 

Plate irders shall not be given an) camber. 



al 



i ,her ... tension or compression, 
29. The butt,.,-, ,u.h of all spliced members, ^ tt d and ri veted to transmit 
.all i„ iremly throughout their whole facesand be ) 3K 









-m 



RAILWAY BRIDGES. 














II.' lull I iK. 



Trough 
Flo ►rin 1 



-• 



Wind Bi ■■ tag 

;in«l ( !n as 

B] Qg. 



Effect [ve 
Sp as and 
Depths. 



Sectional 



the whole stress through the splice. Web splici ihall have double covers oJ n | 

width !<• adinil of sufficient rivets to transmit the whole of the shearing stress at the [oil 
The sectional are i of covers shall be 25 per cent, in excess of fche sections spliced. 

30. Where handrails are required od bridges, they shall be constructed at least l[ 
high above rail level of two lines of gas pipes of I in. internal diameter, with suit] 
standards not more than 5 it. apart, or of open lattice work ur plates \ in. in thickn 
suitably stiffened. 

31. Where trough flooring is used for bridge floors, il shall be designed on the assumption 
thai the wheel loads are distributed over 5 ft. run of the flooi if the sleepers are | 
with the flutes of the troughs, and 1" ft. if they are at righl angles to the flutes, without 
the HI. iv stress exceeding thai specified for the span. A suitable stiffening irdei shall I 
"~ 1 " 1 '" l1 "' centre of the span where the troughs carry a double track. 

32. Wind-bracing and cross bracing between main girders or struts shall be formed 
rigid members capable of resisting tension or compression. 

1 '' '■' R U I'm \ AJSSI MED FOB CaH I'l \l [ONS. 

:::I - K '"' ,1,r P« r Poses of calculating the moments, stresses, shears and working 
strengths, the effective lengths and depths shall be taken as follows:— 

For Main Girders.-Tke centres of bearing plates in the case of riveted plate or 
fcruss - ,1 ' 1 ' 1 ^ and the centres of end pins in the case of pin-connected trusses 

l or ' r08s Girders, The centres of the main longitudinal girders or trusses. 

lor AW Hearers.— The centres of cross girders. 

For Slrnte. The centres of the vertical web pl.ii,> of I ms with riveted con- 

Qec ' lons ; "" 1 tl1 " centr <* of pin. with pin connections, where .1,, web consists ol a 
"'"'V,"" 1 - but wh ,l "- -'' insists oi more than one system the length shall 

';" VA " U be f een the 1"""- "»' intersection or between the points of intei fcion and 
tlie centre of vertical web plates or pi,,. 

tl /; "'. '" '"T" 1 ' n "'" J ' K '" / Pos(8 - Between fche P oi ^ of ,,...-■ ion of 

th " ","";:' ^horizontal bracing with the flanges in weakest plane of bending. 
Bending m Pins.— Between centres of bearings. 

tl ****** l ':>- lh - ' '"■ effect ™ depths of riveted plate or truss girders slu.il be taken 

Z '7 f f* Vlt J of the *M" »* lower flanges, and, in the case of pin-connected 

7" 11 '" , " nl,,s "» P ms » '"" '«"» m any case to 1,- more il,,„ the diatei rertii 

117 ! I e f ^ ' eb Pktes ^ the horizontal llnn,, H; ,t,s. The depth 
*f"* / thG h0ri20ntal r ° WS 0f rivets ^ be used in calculating L 

' Ult;,1 -t' :,n "" 6S "" ^ rivets COni th * ' h - "•"-• «*- to the web plates 

m plate girders. ' 

,. "i T '"; '"" 7"""'' 1 " ** '"' W» for all tensioD members, and shall t» 

T V' pan ? cuttin « "'" " ll "'- ■- ' !-■ i ' 

' .." l '"!■■■ "' '"V"' ' , """ '' V '"'' I' 1 "'"'- «wl :entreac 

lll '"l I •' Ul. In It ;,,,• t,, „. .1...I 1 ,■ . .i . 



lt » are to be deducted from the gross section when computing the ne( 



! '" , L "": SeCt T '"■' *•" '" "'- fa all e .resaio, tnbera. 

, lmi „,/" """"" ' shearin S ■"■'- «* 'ivefa shall I,, calculated or, the, tei be 



fore 






lis titer 



fob 

«i*m 






« 

* 



».l 









m 









U. 







<t 






■ 



I; \1I.WAV BRIDGES. 



435 



The shearing stress on the web plates of plate girders shall be calculated on the 
,,,, n;l l area of the full depth of the plat.'. 

In plate girders the flanges shall be calculated .1- resisting the whole 0! the bending 
afjggj m.I web plates the whole «»f tin- shearin.; stivssi-s, Imt one-eighth of the web plates 
may be included in the estimated sectional areas of the flanges, it" the web plates arc 
suitably cov< red to transmit horizontal stresses. 



! deducting f ( "' five! or l'"lt holes, tin- diameter <-f the hole -hall be taken as 



in. 



1 <!-. 



Ill UCUUAiblUg i>-i ««>^>. •-• -t — o 

: than the nominal diameter of the rivet or boll fur full-headed riveta or bolts 
A \ in. larger for countersunk holes. 

35. All dead loads -hall be assumed to be evenly distributed in the case of plate 

rili .,. , lt ,1,,. [oad brought on the main longitudinal girders from the cross girders 

whenth , , 1 [<3 ft. centres. En the case of lattice or truss girders the dead load shall 

1„. assumed to be collected at the panel joints. 

[ive loads shall, in the cas. of lattice or truss girder*, 1- considered to cover 

th e panel in advai I the panel join, being considered, but the half load will be ignored 

in the calculations. 

,,, hl ,,,,..„,„ ;„, Bhearme -1 bearing stress* on weh rivets of plate girder* 
the whole of the sheL acting on the side of the panel n«t the abutment shJl £ 
,.,.„.„,,,„, : , being transferred into .1. Hang gles .n , d.stan ,,,,1 to th, 

effective depth of the girder. , ., - Vrt 

I' L -lull l„ made for local fcear from h 7 wheel ta* and »> 

, ingintopflang f deck plate girder, and red bearers shall not « 

i l . .»,..,« • shall be proportioned to carry 
I Ota 37. The rerticd cross bracmg betwee n strute sh all l» 1 { ^ 

« 50 percent of the panel I L due to wind, and the strut ■ 



I: i ting in 

\V,.U. 



St uts. 



sist any bending stresses from th< wind loads. 



Depth. 



1 istruction 
with < (pen 

PI 



rwti uction 
th Plai 



< ;<<!,, 



,,„,., ,, , , :::«' rr « —* ' ■ 

noi leas than one-twelfth of lie span. ^ ^ 

;: , ,..„,.,, joi,, spans ma] be constructed wftfa ««.« ^^ J£ ^ ,,,,.. 
With single joists per raU the sp«mg«honU j^ ^ h ,„„,,.,. 10 ,,. 

., .,;,,..„, | bracing between the top flanges, 

when the diagonal bracing maj i mitted. ft ,.,.„„,.. ,•„. the two 

With two joiste per rail the spacmg shod. •■■ ■ J d ,.,_ ,„„:„, 

joisU nnder the nil. ffo dieg ^ ' \ ^The ends of the spans and al 

[tend across the four joists under each trai 
nrid-epan when the length of span exceeds >• 

• . i „, the top flanges maj i» "" 

40. Boiled joint -, - wi* I*** floor TfjL£ at 'same centres » wrth 

structed with either oi ' two joists per ■ •>' 

, , , ,., ir f and sttfening angles riveted to 

11. Eachjoisl Wl« '" ','"' 1 ',,.„„„, II,— 

fc h« web and fitted tighUy between the top and 









X 






*• m + 




V2H 







43 r> 



RAILWAY BIMDCJES. 





I tapth. 




Splices. 




Flan 



"VS. 



¥' 





n < 



Web Plates 
and 
Stiffeuers, 



' irosfi Bracing 

and I ><•( k 

Spans. 

Lateral 
Bi icing. 



Suitable bearing plates to distribute the load on the abutments shall be provided 
at each end of the joists. 

Where handrails are required they shall be carried on suitable longitudinal rolled 
joists, and shall be either of gas tubes with standards oi of plate construction as required. 

Plate < riRDEH Spans. 

42. Plate girders shall, preferably, have a depth of from one-tenth to one-twelfth 

of the span. 

13. All plate girders, whenever it is practicable, shall be built without splices 
but, where this is unavoidable, the smallest numbei of splices shall be adopted. 

II. Whenever practicable, al least one-half of the flange section shall be contained 
in the angles, or else the heavies! section of angles shall be used, and the numbei ot 
flange plates reduced to a minimum. To obtain an even distribution of stress over the 
cross section of the flange plates, they shall not project more than 8 in. or sixteen 
times their thickness beyond the outer line of rivets through the flange angles. 

The compression flange shall be stiffened laterally by cross-bracing frames in the 
case of deck spans, and triangular brackets extending from the top |] :m ^ t „ ,. „.], ,.,,_ 
girder in through spans, al intervals of not more than fifteen times its width. Tl, 
length of the compression flange shall nol exceed forty times its width. 

Main -ir.l,r> „f plat., construction shall, preferably, have one flange plate extending 
from end t<> end in ih,. compression Ham- . ° 

45. Web plan- .hall have angle-bar stiffeners riveted on both sides at the ends 
and inner edges of the bearing plates, and al all points of local and concentrated loads 
and also at points throughout the length of the girder, generally not farther apart 
than tl„- depth of the girder, with a maximum spacing of 6 ft., when the thicl 
ol the web is less than one-sixtieth of the unsupported distance between the flange aj 

All st.ti;.nen shall beai tightly at top and bottom against the flange angles. Ml 
stiffeners over the bearing plates shall hav, pa.-ki,,,, under them of the same thickness as 
the flange angles and as widr as ti„ stillcner angles, but intermediate stiffeners shall 
I^'^Hv. '"' JoSgkd over the flange and-, unless the latter exceed j-in. in thick 
Where practicable, stiffeners shall be placed at web joints. The stiffeners and the rivets 
connecting them to the web plate should be of sufficient area to take two-thirds of 
the vertical shear at the point of attachment of stiffeners to web plate 
, stiffening angles over the bearing plates shall in no case be less than 8J in. by U in. 

'• :/","" T* ' BUffiCient area '" carrvthe '•'""" sheai without exceeding the 
Reified intensity of working stress, no reliance being pL | on the packings. They shall 

be propertied as struts having a length equal to three-fourths of the depth of the girder. 

C(n , " , " i, 1 ,S " ,,, ] "'r dU Bni8hed •" th " «*■ ^ey will, generaUy, have a p . 
corresponding in Wld th to the flange plates, riveted to the end angles. 

B *t °~*«*» insisting of complete frames, shall be used at the endsandal in,,,- 
mediate points where needed for wind and centrifugal force. 

47. In spans with open floors, horizontal diagonal bracing shall extend from end 
P referabl ^ te ^ »g>d members, [n plated floors this diagonal 1 ang may be omitted. 



i 

r r : ii 

Areadp 






; . 



■ ] 'ji! 

itlirtttk 
m 



. 



mA. 






ofe 



it 

- 

90tDd 

'■■><. 
k 



» s 



'iK 






RAILWAY BRIDGES. 



437 



i.il 
i ' • 



General Pro 
portions, 



1 Dstruction 
d Main 
Girderc 



Kivkhi' Tin — on I.viiKK (iiitDEua. — Through Bridges. 

is. Tin- main girders of through bridges shall, preferably, l>e of the single Inter- 
ion type, with inclined end posts and ties an. I vertical struts an.l suspenders. 

Ci rdi ra Bhall lie riveted t<« the vertical struts and suspenders, and a cross girder 

iall be secured to ends of main girders to support the rail hearers. 

Rail b -hall be placed under each vail and riveted to the cross girder A\x-bs. The 

deck shall he covered with buckled plates, riveted to the Hoor girders and to suitable 
intermedi it-' supports. The buckled plates shall not be less than ^ in. in thickness, with 
a buckle of at least 24 in., and preferably placed with the buckle downwards. Suitable 

provisi hall he made for draining the ll.M.r ..>f the accumulation of rain water. 

Horizontal diagonal bracing shall be fixed between the top booms of main girders of 
the necessan strength to transmit the wind pressure safely to the portal bracing between 
the end posts, and of sufficient rigidity and stitiiiess to keep the boomsin line. Where 
there is an open ilo..r, rigid horizontal diagonal bracing shall be fixed between the bottom 
booms of main girders to transmit the lateral stiesses to the piers 01 abutments. The lower 
diagonal bracing shall be rigidly secured to the rail hearers, so as u» transmit the longi- 
tudinal thrust due to train momentum through the diagonals to the main girdersandto 

relieve the cross girdi ra of horizontal bending. 

Cross bracing of the maximum depth permissible with the required headroom shall be 
fixed between the tops of struts, with knee brackets riveted a. top corners to struts and 
cross-bracing and at bottom corners to struts and cross girders, so that a rigid frame is 

formed at each >trut or vertical suspender. 

I ,1 bracinffof the maximum depth permissible with the required headroom shall be 




reduced by <>n«*-half. 



49. The depth ,f mata and creae girder, aha! < be lesa ton onc-ten... of ** 

, ,4 B hall, preferably. I eighth. B.0 bearere Wl Lave » ■!...» 



;ind . • 1 1 1 1 posts shall 
plates of the troughs. Suitable pis 



■ than one-twelfth of their span. one -twentieth of the span, 

The centres oi the main girders shall nut be less vm ^ 

and the height of main girders not more than three times the width 

ee ntres. 

50. The 1 - and end poate Bhall, preferably, be of ^V^""^ ,!',„',',' 

'- r K r, r , ;iJ , ; i . -i >.■.»•■■■•■■ *•"■*•■ 

ai i toe crongna. ou»»»le plate diaphragma ehaJl ^ ........w.-lltl, of U" 

aide plates of boome. The width of I m »haU not » ' ,, , 1M< „f ,1 

oneupported dietai Provieion ahall be made for draunng 

Bcciiiuiilatiuii of ran. water. without aide platea and » web 

■s.n,.s - 1. generally, I f >"'"' ^ lcs ; w ,th „.,,, pl8te , the, ahall eonfona 

plate; but where lacing bars are eubetitated to 

to the ...lea oi lacing bara for compreeei *» ., „,„,„,„,,. l.„i they .nay 

Ti, hall, aa fa. a. practicable, b, *-" "' »f „.,„, ,„. formed of ng>d 

... tolled a, I,.,,-, e pt aear the centre, where 



ie 






. 






» — » 



.^♦* 










I 'onfiti m tion 
• 4 Floor 
( rirders. 



I reneral. 



I reneral 



I reneral, 



P MIH-, 

Machining, 
and Fitting 
ol Sheared 



I 



:•-. 



438 



RAILWAY BRIDGES. 



members. Counter-bracing shall 1 f similar construction to the centre ties, Distance 

pieces shall be used between fche plates forming long ties to reduce vibration. 

The open side of long compression members shall be stayed with intermediate : 
plates or bracing where necessary. The tie plates shall have a thickness of not les 
than one-fiftieth of their unsupported width, except where they are stiffened with 
angle bars, when they may be ,;., in. The length of tie plates at the ends of laced struts or 

lateral bracing shall not be less than the vertical side plates of the main I U s g 

lacing bars shall, preferably, have a thickness of not less than one-fiftieth of the distan. 
between the centres of the rivets connecting them to the main angles and double 
lacing bars one-sixtieth. The distance between connections of lacing bars shall not 
exceed eighl times the least width of the segments connected. 

Vertical suspenders -hall be composed of rigid memb. rs, and shall be proportioned to 
take three-quarters of the stress as a compressive stress. 

All sections shall, as far as possible, be symmetrical about the centre line of str. , and 
all rivets grouped symmetrically about the same line. 

Where angle bars connected by one blade are used as ties, tl. tional areas shall he 

taken as follows:— For equal sides angle bars, 7a per cent, of net sectional area ; t . angle 
bars w,t1 ' sides in the proportion of 2 to 1 and connected by longer side, 90 pel c. 
intermediate sizes shall be interp ilated. 

51. I !ross girders and rail bear, rs shall, preferably, be composed of four angles and a 
web plate without flange plates and the details shall, generally, conform to the rules 
for plate girders. 

Half Through Bridges, 

52. The details shall, generally, conform to the requirements for through bridges, bu1 
all struts shall be formed with plate webs and knee brackets of the largest dimensions 
permissible with fche required clearances shall be riveted to each strul and cross girder. 

Deck Bridges. 

53. The details shall, generally, conform to the requirements for through bridges 
Rigid cross frames and diagonal bracing shall be provided as for deck plate girders. 

Wl •I.KM.W-II IP. 

54. The whole of the workmanship shall he of a first-class character throughout 
and true to dimensions. 

All built members or girders shall be straight ami out of wind and when riveted the 
component parts shall tit closely. 

All girders shall be neatly finished wherever exposed to view. 

55. All sheared edges of plates or bars shall be planed oi machined. 

The butting ends of compression members shall he planed or faced to bear through- 
out their whole faces. 

The ends of all girders that butt or fit against other webs shall be finished tru. 

;l '" 1 n s,1 " :,n ' •"' tn " v,lt lev " 1 required, so as bo give a g I bearing and end angles 

shall be Hush with ends of web plates. 

All packings and cover plates must lit sufficiently close to the flanges at their 
ends to be sealed against the admission of water when painted. 

All web stiil.n.-rs shall be fitted to bear tightly again., the flange angles. 



I ft* 

11*1 

£«* 

• an 









pUei 

. 

a to 






com 

















3F* 



I; V1LWAY HKIIMIKS. 



439 



Poachii 
Drilling vm 

R 



Evel 



Loop Ends to 

Bars. 



i Is to 
B 



VI 1 

Tension B 



Pins, 



Rollers and 
Bedplates. 



56. All rivet, boll and pin holes shall be drilled. 

All rivet boles -hall be ,',.. in. larger in diameter than the nominal size of the rivet. 
Rivets must completely till tin* holts and have large cup heads and be machine 
driven wherever practicable. Countersinking shall he neatly done. 

57 | bars BhaU be formed without welding and shall be slightly stronger in 

the head than in the body of the bar. 

The beads shall be made by upsetting, rolling m- fnrgiug into shape. A variation 
from the specified dimensions of the heads will he allowed, in thickness of .,'._.- in. below 

m ,l > in. above that si ified and in diameter \ in. in cither direction. 

Eyebara must be perfectly straight before boring. All eyebars shall be annealed. 

58. Whn-c unavoidable, welding will be allowed to form the Up ends of minor 
bracing bars. 

\ll screw ends to tars shall be at least ,',, of the diameter larger at the base of the 
t|]lv „, ||l; ,„ in „„. ,„„ lv „, ^ tar and the enlarged ends shall be formed without welding. 
This incre I diameter shall be taken in the ca f bars used without enlarged ends. 

» Kiveted tension tare with pin eonneetions shell have a net h ^ugh pin-hole 

of not 1 1 anda-halfti the net area in the tadyo f tie tar andta w«ntt« 

pin-hole an,l ,1 nd of the tax of at has, I .fifths of the net area. SuffioentrmU 

, |i;i|| ,„. M „, ,„,,,. the thickening plates at the mn-hole efeoUve _ 

The length fro. Ige of pin-hole to the end of tens tar shall not he less 

diameter of the pin. 

61-Allp .hallbetur ■ -^ - ^'JX^ i*^ 

„. , ,,, They shall be turned to s smaller diametei at the en 
L» to pUce with a pilot nut where , rytopr rv, the threads. 

62. KoUere ebaU be tur I, nte.ytog.ug IJ^jJSS^ 

i . i Ttw> hnneues and grooves in uic \<^^ 
the correct diameter from end to end. Lne tongue* 

must lit dnsclv to pivvent lateral motion. 

beds and expansion bearings shall be planed. 



D I. 



Liv< i, ,1. 

Wind h 

nut 



Steel Trestles or Piers. 

•a, , I. L— 11 alcuJ::^ f or the main girders of ft. bridg, 

with the addition of the weight of the pier. ^ ^ ^.^ 

«.«-« »-' -— -^ , "";:;:;: -..—5 

bridge, with the addition of the pressure on la « V <** m „„. ,„,,.. ,,, • 

W J pressure being 30 lb. per sqmu. ««*«* £ o „ „,,. .,.le shall he a, • 

P« quare loot will I the I N" "'■•'" " ite si ,, e . 

sh.-ltrr il... ...neeponding member on tne o H 



/> 



H X 

* 






•*. 



>x 






440 



RAILWAY BRIIm;K>. 



Momentum <>f 

Train and 
( ientl ifugal 
Force. 

Temperature. 



66. These forces shall be calculated as specified for the mail] girders of the 



bridge. 



Impact. 



Permissible 
Maximum 
Stresses. 



Shearing, 
Beai ing and 
Bending 
Stresses. 



1 Construction 



Stability. 



(57. Where the ends of the main girders of the bridge rest upon sliding bedplati 
during movements due to temperature, the sliding friction shall be assumed to be 25 pei 
■•■"lit. of th.' «l«';i«l load upon the bedplates, and shall be added to the longitudinal 
force due to tin- application of brakes to a train upon the bridge. 

Working Stresses. 

(>8. The effects of impact of the live load is provided in the reduced working stressi 
given in the following paragraphs. 

69. i'i) Under drad and lire loath exclusivi of wind. 

The compressive stresses per square inch shall be a fraction of the permissible 
tensile stress per square inch in th.- chords ..1 the longitudinal main girders supported 
by the pier, and shall be reduced by the same formula as specified for the compression 
members of the main girdei -. 

(I>) Under combined dead and I'm loads and 30 lb. wind and centrifugal force, 
or, combined dead load and 56 lb. wind; or, combined dead and !><■■ loads, 
momentum and temperatu/re. 

Legs. The permissible compressive stresses per square inch shall be in< sed U 
25 per cent, over those allowed for the dead and live loads alone. 

Diagonal transverse or longitudinal bracing: 

— In tension. 8 \ tons per square inch. 

— In compression. Reduced l.y th.- formula for compression membei 

using 8j tons as the specified tensile stress. 

Three-fourths of the permissible tensile stress per 
square inch in the chords of the main girders. 

70. The shearing, bearing and bending stresses per square inch shall be calculated 

as specilied for the lattice main girders of the bridge. 

General Design. 

71. The tower or pier shall be formed of four legs or columns battered towards each 
other and braced on all four faces by ri,id diagonal bracing with riveted connections. The 
four columns shall be connected together at the top by a rigid frame of sufficient 
dimensions and strength to support the bedplates of the man, orders; the bottom of 
the tower shall be braced by struts, both longitudinally and transversely, of sufficient 
strength and stif&iess to overcome the friction of the has- plates due to temperatur. 
movements. 

Suitable rotermediate cross frames between the four columns shall be used wher, 
necessary to keep the tower square and in shape. 

rl It is, generally, desirable that the tower shall have sufficient width at the basi 

both longitudinally and fcransversely, to prevent overturning by the assui 1 wind 

pressures, centrifugal forces, momentum of tin- train, and temperature, without dependin, 
upon the anchorage of the masonry pedestals under the legs. This object may, gen. 



Anchoiage Iiolts. In tension. 



***** 

4. Th 

;•••:- • 

uifiadk 
bnenft 

" 
kEtxlefQi 

. 

" - 
■ -■■h'A 
•ititetl 



,: 



'V- 



■ 

littl.; 

H 



•to 







RAILWAY BRIDGES. 



441 



Diagonal 
Bi 



Columns. 



Aim hoi 



tits. 



1„. obtained bj making the transverse width at the base one-third of the height in addition 
t(1 ( || ( . width at the top of the bower, and the longitudinal width at the base one- 
tth of the height in addition to the width at the top. 

Anchor bolts shall be provided of sufficient strength to utilise the weight of the 
masonn pedestals, as an additional safeguard against overturning l>y excessive lateral 

pressures. 

; ; < || lt , tl mis.' .li:i:_ r "u;il bracing shall be of sufficient strength to resist the 

combined stresses due to wind and centrifugal force. 

The longitudinal diagon J bracing shall he of sufficient strength to resist the combined 
i u e to th«- momentum of the train and the friction of sliding bedplates; ox a 
Dgitudinal wind pressure of three-fourths of the transverse wind load, added to the 
fri D of the dead load on the girdei bedplates. 

74 The columns or lege shall be of sufficient strength to resist the vertical com- 
ponents of the stresses due to the wind and centrifugal forces, momentum and tempera- 
ture in addition to the dead and live loads. _ 

Generally, if sufficient sectional area is provided in the logs to resist the dead, live 

and wind loads, and centrifugal forces where the bridge is oi arve, it ■■^« 

to increase th tkmal area for the stresses due to the momentum of the train, tern 

perature and end wind pleasure, as such a combination of stresses is improbable. 

75 , mipil ,i„. the greatest tension in the legs or anchor bom the calculation shall 

taJitaSSo^^ loaded structures. En donble-tra* structures, a tram 

, empty cars shall be placed q on the leeward track. iml ; fHn cr force 

• • *„ ;„ H,a tower lee* shall he made 

76. Fo, v„„, b erecti *•*»*■ ' " of „. % be cut through 

in liatel, above the panal jobte. fhe whofe sect™ o I U ^ 

and the abutting ends machined to , R 1 bearmg II '■ ■ 

„,„-,„„ the whole of the 1 1 ae a el bg strees th, gh th, «•* 



Type, 

Centre Beai 
ingTy] 



Rim I 



l\ 



M" ■ 



ring 



Swing Bridges. 

77. The cbsa of »*« bridge .hall be the cent, ««* — • *^ 

78. I„ ewbg bridges of the eentre ^ ^' .^'tZvf ^ «a»e a load 
aeen of countetweighl BhaU be provided so that ^ fa rf ^ „,„, the 

ol „ i.,,.! 10 then, when the bridge is .!»•** ^ iuoi 

timber deckbg take, ) |--r -"■ 1 '"-' cr '"J 1 '^ „ ull , » ta. b di 

Ti,. ...it.- haUl I cmI Btoel, and shall '''' '*',, ,.,, b , wrought atari of 

5 b. wid the ,r.,M. The roller patb ahaU ' _ of ^ sM|ll , secured to ,t b, 

sufficient width to dietribute the load on the ^ ^ ut i 8 in. apart alternately. 
1 1 bi. dbmeter fulleiv,l bolts ut least 8 in. long, spa ^ s „Hici.-»t strength 

79. Th. tnrntab.. shall I I the latest toprovrf W ^ , , Th, 

:l ,l rigiditj to Burintab its torn, and ***££ „ ^ hbg to the arte. 

whole turntable shall be erected b the anon, 1 




/■••.-* 



y * 





442 



RAILWAY BRIDGES. 



Dri'in i rirder, 







Rollei Paths. 



Rollers. 



Rollei Frame, 



( lentre 
< lasting. 

Rack 
Seg ments. 



Racks and 
I rears. 



End Lifts. 



Tui inn.- 
Machinery . 



Labrii ition. 

Working 

Stresses. 



SO. The drum girder shall be of sufficient strength and stiffness to distribute the 
load u|>>u the rollers. It shall be true to dimensions and be prepared to receive the 

upper roller path. The weh plates shall ' f such thickness thai the rivets supporti 

tli<- lower tl in-e angles -hull have sufficient bearing bo distribute the load from o 
roller to the weh plates in a distance equal to its diameter. 

In heavy bridges no material less than A in. in thickm ■-- shall he used and in 
light bridges | in. in thickness. The connection to the main girders of the bride 
shall be designed <»f ample strength to resist the shock in starting and stopping the 
turning motion. The girdef shall be proportioned as for plate girders. 

81. The upper ami lower paths shall be of cast steel, machined and finished true 
to dimensions, at joints and on bearing surfaces. The drum girder shall be adjusted 
to the upper path by steel foldihg wedges about 30 in. apart ami aft.-rw.inl> drilled 
for 1-in. diameter bolts. After erection at the site, the spaces between the drum <*irder 
and the upper path shall be filled solid with rust cement well stemmed in. The lov 
roller path shall have suitable cover plates at the joints and shall be secured to the 
masonry by lj-in. diameter fullered bolts 8 in. long and about 18 in. apart alternately. 

82. The rollers shall generally l t solid forged steel secured to the inner and 

outer spacing rings by holts passing through theii centres. Suitable gun-metal liners 
and collars shall be provided al all bearing surfaces and provision shall be made at 
the ends of the rollers for adjustment. The rollers and the surfaces of the upper and 
lower paths shall be turned to form parts of conical surfaces with a common verb 
at the centre. 

83. All radial ban and the roller frame of the live ring shall be formed of rigid 
members with suitable tangential ban to maintain the relative motion of the parts of 

the frame. 

84. The centre casting shall have ample strength to centre the bridge and to prevent 
its displacement from objects striking the bridge. 

85. The rack shall be of east steel in short lengths and shall be planed on t! 
bearing surfaces and joints, and connected to the lower path with fitted lug bolts. 

86. The cast racks and gears shall have the pitch lines of teeth exactly in the 
same plane. Gears shall be true to bevel, truly circular and bored at right an 

to plane of action, to lit the shafts accurately. The teeth in geare shall be raachu 
cut, where specified, to exact pitch and in all cases shall mesh accurately. The hul 

of gean shall be machined. 

87. Kllective cml lifts shall be provided which shall give the necessary reaction in tl 
shortest time to prevent the ends of the bridge being raised by a load on the opposite arm. 

88. Efficient power machinery shall be provided to open and close the hud-., in th 
specitied time. Hand-power machinery shall also be provided. 

89. Suitable means of lubrication shall be provided for all bearing surfaces in motion. 

90. The unit working stresses in main girders shall be 10 per cent, less than tl. 
for simply supported spans. The length of the long arm shall be the measure of the 
span for comparison 






tf 






^ 



ItkJdM 

C 
C 

c 






( «8 ) 




» J 



Road Bridges. 



1 ,< "APING. 



Dead Loada 



.,1 The ,i,.,,,i [oad shall <•< -usi^i of the whole weight <>f the steel superstructure and 

l _ : ..\ »1... mafamalfi f. Miiiitur t1»i> l-i n ilvvn \ •-; i-liMtillcl-; l.'clli« fnotWftVS 



live Loads. 



exist 



'|'| 1( . dead load Shall eonsisi <>i me wnuie weigiu <>i m« Bwsci j,(([H'i.Hnii'uiur .ii 

aIlV cast steel or ironwork, th< iterials forming the roadways, channels, kerbs, footwa; 
and handrails and the fcramwaj tracks, water, gas and electric mains, if such exi 

upon the bridge. t 

The pennanenl waj for a tramway track shall be assumed to weigh 100 lb. per 

lineal foot per track. 

Foi spans of leas than J00 ft., the total dead load shall be assumed to act at the 
loaded For spans of 200 ft. and over, the total dead load shall be distributed 

:lt top :lllll bottom chords as in paragraph 9 of Railway Bridge Superstructures. 

92. For fehe purpose of estimating the probable Live Loads, the bridges shall he 

divided into three classes as follows :— 

Class 1. Roads with light traffic, such as branch eountry roads. 
Clasa ii. Koads with occasional heavy traffic, such as main country roads. 
Clasa [IL-Roads with continued heavy traffic, such as in large towns and 

in manufacturing districts. 
The following live loads -hall be assumed:— 
( a \ Pedestrian Traffic. Roadway. 

*1 '. ■» '»™ ^ilutt L Z to he less than 

increase in the span ol J) it., dui 

56 lh. l-f square foot, 
,,„ bhe floor girders. 84 lb. p., ^ t,,t for aliens. 

Claaa ii F„r the main trusses and flooT girders. 

[ncrease Class L by 25 per cent. 
daaa m For the main trusses and Boor girders. 

[ncrease Class L by 50 per cent for ro;uhv;lv , 

Alicia .-Pede*trian traffic. Wj^ Job . £-^ 

DU I in no case to exceed 84 Lb- I 1 

(6) Vehicular Traffic. , f ^tres and 5-ft gauge 

C^ X ._A vehide weighing 4 to* > on two axles 6 

and occupying, wid* «i . ^ us *„* and occupying 

n ,„„ .a toadroUei « • ^.TA *»« "* T^ 

■ •«* " f 10 "" " ,ll,,w ,0, 1,-r .■-' «»'• ""'' v ''" ,<! 

8J tons e..-l. «»•> »"■'» «""■' 1L Wdge at one toe. 
eLine with its trucks! *u PJ the 








mcvoN enpi*E* 



«&. a&- 







*> 



V 









""" 'floxo *oue* 






* • em ** 








k<>Ai> i:riim;ks. 



Class Iir.- A road roller, as in Class II., or a traction engine weiehinfl 

20 tons and occupying a width of 10 ft., follow* 1 by ;1 L.a.l.-.i 
boiler trolley weighing 32 tuns. Only one engine and troll 
to occupy the bridge at the same nine. 



fe— - 14 ' 






Electric 
Trams. 



W incMV-s 
sure, 



ST&a 



— ■.-**—-« o- 



Sixmos 

vmm 






BOILER TROLLEY 



"T 

- 



lis 




--72: 0---SH 

4 ton* 



INI .III 







£ _ 



TfiACTIQN £NGINE 




" 



STons 



6Tdruf 



111UI 

4 tens 



93. The following Inn. Is per Lineal foot per track shall be allow,. ,1 for tramways 
The car is assumed to weigh 16 tuns, and to be 25 ft long on two axles 7-ft. 
centres by 1 ft. %\ in. gauge, and occupying a width of 10 ft.: — 

1<» cwt. per lineal fool plus an excess load of 8 tons anywhere <>n the track foi 
a span of _o ft., the load per lineal foot being reduced by \ cwt. for each increase 
in the span of 10 ft., but in no case to l>e less than 7. 1 , cwt. per lineal foot. 

The live load stresses shall be the maximum strokes produced by the pedestrian and 
vehicular or tramway traffic taken together or separately and considered as stationary or 
as moving in either direction. 

Cn estimating the stresses due to the combined pedestrian and vehicular or tramway 
traffic, the width of roadway occupied by the vehicular traffic shall be considered 
occupied by the pedestrian traffic. 

Unless otherwise specified, the tramway tracks shall he assumed to tpy the centre 
of the bridge in the case of a single track, and double track- shall be placed symmetrical!) 
about the centre line of the roadway, with a distance of 10 ft. between their centres. 

Vehicles and traction engines, with their following loads, shall be assumed t »upj 

■'">' pari of the roadway, and in calculating the stresses in the trusses their eenl 
hues shall be assumed to be not less than 5 ft. from th«- inside face of the main girders. 

Traction engines and tramways shall not be assumed t :cupy the hrid-- at tin -,i.,r 

time unless the width of roadway exceeds 30 ft. 

Unless tramways are specified, the l„i,|.,. .shall h. designed for traction engini 

and other vehicles. 

94. The wind shall be assumed acting in either direction, horizontally, and to be 
blowing at a slight angle to the axis of the bridge, so as to take effect on the <-^.,.,<\ 
areas of the floor and of both windward and leeward girders, except when the latter 
temporarily screened by a passing vehicle. I >ne-half of the exposed surface of the leeward 
under shall be included in the total area acted upon by the full wind-pressure, except wh. 
the distance between the main girders is more than twice their depth, when the whole 
exposed area of leeward girder shall be taken. 

With no vehicles or live load on the bridge, the wind-pressure shall be assumed to ! 
o0 lb. per square foot ; and with the live hud on the bridge, at 30 Ih. per squar, it 

oi exposed surfaces of vehicles and bridge. The vehicles shall be assumed v. 

the whole length of the bridge and be taken at 8 square fee, ,,., lineal foot, and the centre 
oi pressure oi the surface ,. 6 ft. above floor level, except in the case of trams. where th 
surface shall be take, at I J square feel per lineal foot, and the centre of pressure at 8 ft. 
above rail level. The wind-pressure on the vehicles shall be treated as a moving load 



■ 

. - 



* 






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■a fa 









; | m 1 

vMm :— 

al 

W 
-The< 



% 



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Momentum 



Centrifugal 

F.irce. 



Road bridges, 



445 



- 



■\-\ w maximum stresses resulting from either condition to be taken in determinin 
T l |( . ,, n -\ sectional areas of the parts. 

In providing fche necessary anchorage for the structure, the bridge shall I.e. assumed to 
l„. covered with a train of empty vehicles weighing 6 cwt. per lineal foot, or tram 
cars weighing 10 cwt per Lineal foot, and the live load placed on the leeward side of the 
bridge. 

95. Special attention shall he given to the details of the structure to provide for 
the longitudinal stresses resulting from the tractive force of the trams, or from the sodden 

application of brakes to the tram while on the bridge, and the horizontal force resulting 
h,,,,, 5UC h action shall be taken as one-fifth of the weight of the tram. 

90. When a bridge is on a curve, the resulting horizontal stresses due to the 
centrifugal action of the rolling load shall be provided for. 

In stimulating the resulting stresses, the wind shall be assumed to be acting in 
the same direction as the centrifugal force. 






K 



■ 












af«* 






Working Stresses. 

tor-:. 97. To provide foi the effects of the dynamic action of the live load on lightly loaded 
rider. ... m. ml..-.- "f u-ir.l-.-s, the live load atressea shall be increased by 25 per cent, 
fa, I ;„■ ,f the main girders and S3* per cent in the case of the fleer girders. 

98. All bridgework and treetl. piere shall comply with the whole of the following 

u ""' ' conditional— 

,. The , hi I atr uniting from the live load, «_^™*~2 

and centrifugal to, ahall nol produce a greater tens.le *-J^JJ 

„,- , Usfe limit, ... equal ... three-tenths of the mmunum "".mate t, 

.„,!,. „f .he ,,,,,,,.1- nor -re t, the corresponding compresstv, shea,,,., 

,„,„„,„ : „„, beading Presses as hereinafter set forth; but- 

of wi,„l. aentum and centrifugal force, shall not produce g 

stresses than those tabulated below. 

99. For main girders, cross girders and stringers- 
Bottom chords 
Diagonals 
For wind-bracing 
For floor suspenders - - "' at the centre portion of 

Note. The 5 tons stress on the diagonals will apply to , tg. ^^ ^ apply to 
the span, and to the counter-bracing at the same P"^^ J stresa are not so greet. 
those a1 the end portions of the span, where a ween fte two limits, 

[ntermediate diagonals will be subject to stresses lying 

«# the compressive flange Baa 

100. For plate girders, the gross section* ^^J str6 sses persona* »<* 
be Less than that of fchfl tension Hang' 1 , noTsn t( . lisi i e stress. 
be more than 85 per cent, of the corresponding spec. 



Tensile 

sses, N"t*T 
v CtlOIL 



tons per square im-h 



5 to 7 



8J .. 

'2 >> 



V 



51 

15 



I 



Stresses, 

tion 









#• ••» 



.^* 




Alternating 
Stresses. 



Shearmp, 
Bearing and 

I '.. li'lllILT 

Stresses. 



i;«»AD HKiniiKs. 



Fortress or lattice girders, the compressive stress per square inch shall in the ol 
riveted members not exceed the fraction (0.95 - 0.003 r) of the corresponding specified 
tensile stress; nor, in the case of pin-connected members, exceed the fraction 
(0.95 -0.004" r ), where r is tin- rati.. ..f tin- l.ngth of the unbraced portion of a men to 
its least radius of gyration : nor in any i as. shall it exceed 85 per cent, of the said U 
stress. No compression niembei shall have a greater Length than 120 times its 1. 
of gyration, except for wind-bi icing, where it may have a length not exceeding 140 tinu 
its least radius of gyration. 

101. Members subject to alternate tension and compression shall be proportioned as 

struts and bave sectional areas equal to thegreater area added t ie balf of the I. 

area required f..r tl..- compressive and tensile stresses considered independently, except in 
the case ol wind-bracing, where the sectional area ma) be proportioned to resist the 
greater stress. 

102. The shearing, bearing and bending stresses pei square inch shall not exceed the 
following limits : — 

(1.) In Truss or Lattia Girders, and all Web or Flangt Joints in PlaU Girders. 

(«i For machine-driven rivets and turned bolts or pins of a driving fit 

Shearing stress ... J of the permissible maximum tensile stress pel 

square inch in the girder or mnnher. 
Bearing stress ... U lilll() 



l'.-'inliii- >i lvss 



li 



ditto 



1 1 Hers and 
Bedplates. 




(6) For hand-driven rivets having a length over four diam.-ters. 

The number found for (n) to be increased by 10 per cent. 
('•> For ordinary black bolts. 

The number found for (a) to be increased by 25 per cent. 
(2.) /// PlaU Girders. 

Shearing stress in rivets ... j Q f the permissible maximum tensile 

stress per square inch in the girder. 
Shearing stress in web plate .. . \ ,ij Uo 

Bearing stress on rivets ... \\ ( ii tto 

(3.) Bending Stress on Members Subject to Direct TensUi or Compressive Stresses. 

Where such stresses occur the member shall be proportioned to th. 
algebraic sum of the stresses resulting from the direct stresses and three-fourths 
oi the maximum bending stress, and the stress per square inch shall not 
exceed that permitted for the direct stresses. The member shall be consider, 
as a Lea.,, freelj supported at the end.. ,,,1 the bending moment at the ends 
shall be considered equal to that in the centre but in opposite direction. 

103 The pressure in pounds per lineal inch on rollers of rolled steel shall not exceed 
300*, where rl equal, the diameter of the rollers in inches: in the case of live 
under swing bridges, the pressure shall not exceed three-fourths of this amount Bed- 
plates and rockers shall 1 f sufficient area and strength to distribute the load 

""' ma f onry wlfchou1 exi ''^ ;t I"'-"'-" of 16 tons per square foot for hard ston. 

" L " l,,lls l- -l"a.,- l.,.t f..r ,ranite,and 10 tons ,,r s.^a,,- f.,„ t for cement .,,,0 

(4 w 1). 



r 






m 






' v. 






- 






UT.Cn 

mat 



. -nil 
put like 



I 

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- - 

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■ 



1112 

- '■ 



ins 



ROAD BRIDGES. 

lui Whore wrought iron is used for an) girder or member of a bridge, the working 

shall be 80 per cent, oi those specified in the case of steel for members subject to 

tensile and bending stresses, and for shorl compression members; 85 per cent.fbi long 

impression members, and 90 per cent, for members subject to shearing and bearing 

stn — 

105. Where the str< resulting from the dead and live loads are combined with 
fl,,,,,. ,],,,. I,, the wind alone, or with the wind and centrifugal force, the preceding working 

, uare inch may be increased "-'5 per cent., but in no case shall they exceed 
three-tenths of the minimum ultimate tensile strength of the material. 

106. Tin- unit stresses on the main girders of opening bridges shall be reduced by 
lit per cent, 

107. Connections shall be proportioned to develop the full strength of the member 
notwithstanding that th< calculated stress may be less. 

Structural Details, Etc. 
108 The paragraphs on p 432 to 134 of the Railway Bridge Specification shall 

apply senerall) to r 1 bridges unless otherwise s, ified. The types of bridges ^ suitable 

fo particular spans may be modified, and a nnmmu^ei S U oi Alh^M ioot ^ 

p.,,,- £* all be provided having . height above tl, footways ..» a ''^ ^ ' ' 

rf resisting a horizontal pressure of about 56 lb. per lineal foot apphed at the coping level. 



TnnberFloors, 



Types of Bbidgb IfLOOBS. 
.09. When timber n .are, ifled, the ^^"££,5 % £ Z 

« <*»* r f t is ^r- tTm iLy ^ ** 

stringers, and from 8 in. to 1" m. "• "»■ ""> 

open, space*. ft l wa y, it shall be 1J in. thick 

When an additional wearing surface is used I", tn ^ j^ .^ .^ , |otlom 

.,,,,1 ,„„ ceding 6 in. in width, bud *££% m a^nally with 1-.". cpen 
II hay, , minimum thickness ol 2j ">• ana 

spaces. ., ,,,„,.:,... thev shall not !«• l'«* t,,an 

VFhenw ..-,, joist. - u»d » currj "" . ' ^ (1 „.„ ,|,,Un-. They shsll 

Sin. in thiol -. greater in depth H ' " ,_,„,,..,, „ v ,, ,!,,„■ seat 

b ,ccd not more than 8| "■ apart •*■** ^teougW f '*'<■' '- v "' l- ' f " n ' '" 

mgk o, II gbdei, bj at least J in-, and ■ *• "I ' ■ , , bj ,,,,|, other so ,- to 

planl fixe! The inter liate joists shall, p*«J* ^J^ by j ». to .Off 

extend ove, the fall width of the floor girder and shall ^ £ ^ fc ^ rtlrl!ll .... 

a bee circulation of air. The outer joists shall ■ 

from end to end of the span. |u . Hoor girders by hoo 

The w I.,, joists shall be securely fastened .,, „, , ; „ , J( „ t 

in. in ,1, ter. The I ' £**£ naUs b b P '- -- * 

vl„,l, ,, „.,. I, two Tin. bj | in. cut spikes, ■■■ 

top wan,:, surface nailed to the planking. rf niit ,,,.. than 9 "'• ■ 

Wl,..,.. wooden joieto are not used, a w W - 




£2 






V J 



??» 









44S 



mun hrid«;ks. 



Solid Floors 



% 










Steel Plate 
Floors, 



Flat Plates, 





and 4 in. In thickness shall be securely fastened to the top flange of the flooi girder 
by coach screws § in. in diameter, and spaced nol more than 18 in. apart alternately. 
The planking shall be spiked t«> the sleeper. 

Wheel guards of a cross section not less than 1 in. deep by 6 in. wide shall be provided 
on each side of the roadway. Thej shall be blocked up from the flooring by blo« 
: " ''• 1S| '- '"• long by 6 in. wide and 2 in. Murk, and spaced not more than 7 it. 
apart centres. These blocks are fastened to the floor by four H-m. cut spikes. The guard 
timbers are held in place U a bolt through the centre of each block j in. in diamel rid 
passing tlm.n-h ,1„ j,,i s f beneath. The guard timbers shall be spliced over a blockii 
P iece with ;1 ia P Joint at least 6 in. long. The guard timers .hall l.o protected at 
their upper corner next the roadway bj steel angles at least 3 in. I.\ 3 in. by J in., sei ireh 
fastened by countersunk screws about 18 in. apart. 

The footway planks shall be 2 in. thick and about 6 in. wide, laid with I .,,,,■ 
spaces. Each plank shall be spiked to the joist or sleeper by two 8-iii. cul spikes. 

All planks shall be laid with the heart side down, and .hall have full and even 
bearings and be firmh attached to the stringers. 

110. The materials forming the wearing surface of the roadwayshall be laid upon a 
bed oi gravel concrete of a thickness of at least 2| in. over the highest point of the floor 
girders t, h«- ...v.-n-d. excepting rivet and bolt heads. The concrete bed shall be cambered 

at least! in. for every 5 ft. in width oi the - Iway to provide suitable transverse drainage 

H '"' kerbshalJ '"' formed of solid granite 12 in. wide M > .... d„„ projecting nol let 
tnan4 m., and not more than 6 in. above the channel. 

The channels may be formed either of solid granite 12 in. wide bj 6 in. deep or 
tll, 7 ° r m f e P«»"e3 curses of granite setts, each 6 in. deep bj 1 in. wide The 
channels shall have a fall of at least 1 in 50 towards gulley gratings 

Suitable gulleys shall be provided ... drain the channels clear of all par,, of the 
metal work- 

The materials forming the wearing surface of the footpaths shall be laid upon a bed 

°' "■ IV " ""■ " f ••' "'"' > * has! U in. over the bighesl poini of the foot 

*K girders, exeeptmg rivet and bolt heads. The concrete bed shal] have a .,11 towards 
""' chant >elB of al t 1 in 7l> to provide suitable drainage 

Where ordinarj macadam is used for the roadway, i« shall have a minimum finished 
« ■'■■!*".■"- oi 6 m, tar macadam of * in., and asphalts of 1.1 i,, for ligh< traffic and 
-in. for heavy traffic Granit, setts ma, be 7 in. long b, S in. deep, or 6 in. b, , in., 

'.:. '"•.'• V '' .'I'' , N,f| -" I'-" 1 - Mocks are generally 9 in. long b, 6 in. deep bj 

3 in. wide, and hardw I paving blocks 9 in. by 3 in. by 5 in deep ' 

Where asphalts is used for the footpaths, it shall have a mi „„ finis I thick- 

"7 ""' '"V ' l "'■ "" '" "' ' in - '""' ,: "' I*** "f 2 in. Stone paving 

slabs are generally 2 in. thick. 

. . "'";". " '. M, " k P*""* h "-1 for the roadway, it may rest on a timber Boor 

of from f ,n. to , ,„. m tlli ,. k , „.,,-.,, ., s ,.,., ii . | . |v ^ , ^ ^ ^^ 

1... .ill"' I''." ,"'",', l :'"'* S f ° r CMTyiDg "' e materi »h forming the road and footway may 
be either fiat, buckled, nii-ved oi ingated. ' ' 

s,„, Hf' ","' fVt"" '' l; '" '"' ""'""' on i '" ed «" to the Boo. girders or intermediate 
rapports, and shall be suitably stiffened at intermediate points The plates shall bav, 



>W* 









:■ 

TV 



5ar rrren 

The 

m 

p. 

Dm 



ft.pl 



Tt 



S 



- 









:- 



K*4 



M 



Kmyh bridges. 



449 



I kled 



,, m f not less Ann H - - »* *» T»° -ete shall not be le» « i in. 

U, diameter end al (in. pitch. 

, . , , ,.♦„ i,,il be riveted on all edges to tin- door girdem 01 
113. The buckled plat" shaU ^ ,.,„„„, ,, „„ t IeM ,,,„ 

W ^^^vet^hS not be less than | in. in diameter and a! t 6 u,. 

-"":,-,,„, shell* -ft-* not less than 2 i iorless« 

0, . steward* bet a the aupporte. 

ll4T | ^d plataa ahaU generaUy be Pb ^J^JS^ 

Thcv .,, ; ,u bav, aflat bearing of no - nds t0 the web plates ol 

L rivet* • * *- *£-*£ * ^ J. ^bar. The rive* shall 

^rfheS"^- - "tZ^ 3 , .rlesstbano « atbotthe 

• n „. ,,1.^ ahall have ■ camber ol not 
clear distance between the supports. mB* nnder the 1 h. 

Provision shall be, leto P"^* 6 /* ^ble angle or tee bars nveted to * 

The plates shall be surtablj stiffen. . 

underside. 



i 

Plal 



'"'- i „ mrrlars or supported 

ie. d to it by one. I "vets . wheK the, abut upon 

'•'"■ P itch - , , , hall be riveted to their supports, an 

Cbe corrugated plates -1,1 ' „, ,,„.,, corrugation and totn 

a web plate, a cleat eheH be meted Jo the top ^ ne-twenUetk o 

Th, irrugated pUtes shall nol 

l .M«V«ft: ■ • ....1.1 



MllllUlUlil 

Thii kne«H oi 
Flooi Pla 

Jai k Arch 



diata! between the supports. ^ , u , „,„!,, 

„,,,,- I plates in the fl -hall 

the lwa 5 or footway* [ brindle bricka in cement 

!„.«- I—*- £ °£le^ 'shall be ^^ 

or sLfordshire b bricks I -*J^ ,,..,..„ omfla^ ,,,„, , ,„ 

ol a< to two parte of clean sand an The eyandrde shaU „„„. 

oement concrete (6 to 1) to a levelof „ •.-'„,,,,,- .1 

The rise give • «* fl^rfers supporting * but 

al t level with the top flsngo oJ * ' _ a _ 5 r. apart, shall 



one-fifth oi the dear span. aiameter and not 

Tie bolts, of no, less 1 • 



:,:,„-..,- ,,., .east. '-- . 

, sed to prevent tl * *-** gh to jack ■*-» ^ ^ in two laye* 

To prevenl moisture percol tag £ ,. u ,, v . ;ll „. 

shall bee, I over the whole urface _ 3* 



*■" ta S| " r: ' ° 7 i the kerbs al - - ■»■ 

Oi J in. and b>l>ped "P : " "" 






i 




( 450 ) 



Standard Clearances for Bridges. 



RAILWAY BRIDGES. 
DOUBLE LINE BRIDGES 26 FEET WIDE 
SINGLE 0° 15 D* 







P •?:-?*<>.■ 



Inside t r a& i 
Qultr Girder 



Oe 



fetta 
Mb- 



Mm- 



ROAD 8R/DGES 
HOTL ParapAs on Bridges &vtr nzO**<yr$ tc *e at least 4 ft high rn the bruin* AJft.cn the appvaxhes to u 
Hh/r' Tram*avs cross the bndaes -i rnvutnum head room offtft should be provided 




TURNPIKE ROADS. 
Ma*x. Gradient I in 30. 







M><? 



2 






260' 



I 

I 



I 



I 



ffOAO LEVEL 






PUBLIC CARRIAGE ROADS 
Miur Gmetunl hn ZS 



*--/ 



j? 



i 
i 



5 



9 0' 



I 

I 
I 
I 

3- 



72 0' — t— i 



ROAD LtVLL 



PRIVATE OR OCCUPATION ROADS 
Mojo 6radde7U Jt/tlG 




V 



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v 



Iffv- 



Pi 

; 









tan 



v, 



•M-2 






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> 



General Specification for Workshop 




Buildings. 



CONTEXTS. 



Description. 
Material. (Page 452.) 



General - 
Rolled Sted 
Rivet Steel 
Cast Iron 
Wrought Lron - 

Timber - 

i Galvanised Sheeting 

Painting 

I rlass 

Slates - 

Lead Flashings - 

Water 

Sand 

I ement - 
Bricks 
Mortal - 
i 'oncrete 



Section. 

- 1 

«■> 

. 3 

- 4 

- 



. «; 

. 8 

- 9 

- 10 

- 11 

- 12 

- 13 

- 14 

. 15 

- 16 

- 17 



LOADDfO. (Page 4.V4.) 



I . aeral - 
Dead L ads 
Lnt Loads 
Wind Pressure - 
Snon Load 
Minimum Bool Loads 



18 

L9 

_■«, 

21 

22 
23 



Wowmro Stwmsto. (Page 456.) 

I li aeral - 

Tensile sin'-su- 

' impressive stresses - 

Shearing Stresses 

B< wring and Bending Stresses 

I ombined Bending and Direct stresses 

Loads on Masonry 



Description. 

Stkitti km. 1)ktmi>. (Page 457 

Minimum Sections 
Lacing Bars 

Tie Plates - 

.Joints - 

Riveted Connections - 

Purlins - 

Roof Trusses - 

Roof Girders " 

Crane Girders " 

Columns- 
Framing for Corrugated Sheeting - 

Dl.i". »n:d l'iaci)i-_' 

- 

Ventilators - 

Weather B< larding 

Timber Framing 

Steel Framing for Brickwork - - 

dates - _ 

Putty Glazing - 
Patent Dry Glazing 

Corrugated Sheeting - 
Galvanised Iron Flsehinga - 

Galvanised Iron Ridges- - 

Skew Timbers - 

Slating - . 

Gutters and! ^p^ - 

Roof Gangways and Bno^i 

Roof Ladders " . 

Brickwork - 

Pointing' 
Damp Course - 

Timber Wall Plates - _ 

f-'^- ,,s ;;::: Ins - 

Foundation* un,lu ^ 
Foundation Bolts 

Temperature 
Workmanship 



Section. 



31 
32 
33 

:u 

38 

36 

37 

38 

39 

to 

41 

42 

4:? 

44 

45 

46 

47 

48 

49 

50 

51 



• ft 



* m *i\ 






i ;•• i. -i.il. 



R .11., 1 Steel, 



Rivet Steel 



I !ast [ron. 



Wrought [ron. 



'i»* 



I'linl ier. 



< JalvaiiiM-d 
Sheeting, 



Painting, 



S3 



( 452 ) 



General Specification for Workshop 

Buildings. 

Materials. 

1. The whole of the structural portion, except the tee astragals and ventilatoi standai 
3hall he of open-hearth rolled steel, It shall be free from laminations or surface dcfe< 
and shall coiuplj with the specification of the British Engineering Standards Commit for 
structural steel. 

The tee astragals shall be generally of wrought iron, and the ventilator standards 

of cast iron. 

2. snip- cut lengthwise or crosswise shall have m ultimate tensile strength of 
not less than 27 tons, dot more than 32 tons per square inch of original section, with 
an elongation of at least 20 per cent, in a length of 8 in. 

3. Rivet steel shall have an ultimate tensile strength of not less than 26 tons, nor 
more than 30 tons per square inch of original section, with an elongation of at least 
25 per cent, in a length <>t s diamet< rs. 

4. All castings shall l f th, l„,t t,, n -h grey metal of such a strength that 

1 bar ' "'• thick l,v - "'• deep placed upon bearings 3 ft. apart will sustain without 
fracture a weight of 27 cwt. placed at the centre with a deflection of not less than .'. in. 

5. The wrought iron used for bolts or bars under 2 in. in diameter shall have 
an ultimate strength of not less than 23 tons per square inch of original section with an 
elongation oi not less than 15 per i ent in 8 in., and shall bend double when cold without 

• rack in 

6. All timber shall be of the best quality, -awn true and out of wind dressed 

where specified, of full size and h^ from shakes, large or loose knots, decayed w I 

"ft wam 1| " ] '"' "'• othw defect which would impair its strength or durability. 

All externa] exposed woodwork, except weather-boarding, shall be of red pine oi 

equal. Weather-boarding shall be of white pine. Where the w Iwork is not exposed 

!" ,1 "' weathei " ^ ' f *Kte pine or similar quality, exeepl the main horizontal 

beams in timh,r f millilll , f which shall be of pitch pine or other approved timber. 
1 imber shall nol be dressed unless specified. 

7. The corrugated sheeting -hall 1 f first-class quality and well galvanised with 

Mt ™* ■' oz - of spelter per square foot. Unless otherwise specified it shall have a thi. km 

"' - Sn - 18 W. G. before -.ilwini-im:. 

Flat sheets shall be galvanised, an.l, unless otherwise specified, shall have a fchicknea 
-I An. 16 \Y. <;. before galvanising 

8. The whole of the structural work before leaving the shop shall be scraped clean 
•""1 receive one coai of the best oxide paint. 

A \' 1 "'"' two surfaces "" 11 " i" contact, one of them shall receive one coat of paint, 
' nU P"*" which are "" 1 essible to painting after erection shall receiv. two 













*t 



.:' 









<ui 















■1)61 









,,jh 



1 
10 









W'nKKSHOF BUILDINGS. 



453 



1 



"P 






Glass, 






. -: 


















. & 

A1* 



- 



Lead Flash' 
tags. 



W: 



v ll'l. 



Cement. 



Bricks. 



Mort 



ai . 



,.f paint before being riveted together. After erection at the site the whole 
, hl H reC oive one finishing coat of an approved colour. 

■pi |( , rt ^ ,,,- columns and other steelwork which come in contact with brickwork, 

maaonI y | OT concrete shalJ nol 1"' painted or oiled, but shall be scraped free from 

ini ', BQa j] rece ive a coat oi liquid corneal applied with a brush as the steelwork 

is heing DU iit in. This cement wash shall be applied by the contractor Eos the 

brickwork, masonry, or concrete. 

Galvanised sheeting shall not be painted unless specified. 

AU w l W ork in gates shall receive two coats of paint, one before and one after 

"'"" aii w Iwork in , I gangways shall ive , coat of tar after erection. It 

shall not 1"' creosoted unless specified. 

9 . The glass on the roof slopes shall be of the best quality of rough est British 

^ i^SfSj^ the glass shall be of the best c.u.Utv of rough cast British 
plate, -V in- ™ thk-kness. ^ ^ , in> 

M tuST2 1 > * weU •— •* k, """ k " 1 """ a ' „ , , 

10 . SUtes shelf be of the 1 .«*» — * in the local!*, and shall be p*4 

Borted and squared. ^^ 

11. Where - I lead is used for -J- -J ^JtrT^^^ '" 

than 4 lb. per square foot, and for skews liable to be used 

6 lb. per square foot. lam TO ter free of charge, and lay 

11 It is assumed « : the proprietors will supply olean water 

a pipetoa conrenieni point on the site. ^ 

, , „ . . ,.„ m «h and sharp qnaUty, eutolj fre. 

13. All sand shall be ol large, roug 

matter or other impurities. WH ieht, fineness and 

14. Al! nt shall be the best ^^£j£'«-i*C «"• 

q Man Ply *ith thus, n* is- • _ ] ,„,„,,.,„„„,. 

15 . The bricks for walling shall bs unrform* J a ^ t „ ,„,„,, three course, 
s M „ ; „, and thoroughly kiln burned, and « . ; > will not he used, nor hall 

to the foot Wn Bt, Boft, bully or k.ln- ■ . | 

broken bricks where whole bricks can be empl ^ ,,,,,,,,,4 ....„,..». to 

16. (.) The tar for building shall becompW ^ ft ^ , mposed of 

t.„ pari of sand h, sure, and for , ting a 

»1 parte of Portland cemenl I ■• i of weMakedtae and ^ 

(6) Where s, ified, the mortar may b ^ .„ tlu , ,„„,„,.,„, " ,, 

rive, I. entirely free from sail or other im, ; ^ ^ly muced and 

„,,,„■ (dot lime to three parte by measur. 

before the work is commenced. 



" t 






g 



2T 



vv? 



^>**- 



454 



WORKSHOP BUILDING. 



Ci 'in rete. 



I lead Loads. 



Liv.-Lo.hl-. 




Wind Pres 

SUM". 





Snow Load, 





Minimum 
Roof Lh.m1>. 



17. The concrete for wall and column foundations shall '»• composed by measure in 
tin- dry state of one part of Portland cement i" two part- of 9and and four pari 

iif bricks broken to pass a 2-in. ping, or part of Portland cement to 3ix parts of river 

gravel containing a suitable proportion of sand. The whole of the materials shall 
prepared on timber platforms and turned over twice while dry, after which sufficient watei 
shall be added and the mass turned over until completely incorporated. The concrete shall 
be laid in the trenches and properly punned until it shakes like a jelly. 

Loading. 

18. The structure shall be designed to withstand the following loads : — 

19. In determining the sections of any truss, girder, or column, the total dead weight 
coming on such shall 1"' taken into account. 

20 The.-.- shall include the maximum loads from all travelling, jib oi mono cram 
including their own weight and the pull from belting. 

(a) Provision shall be made for the effect of the sudden application of brakes to thi 
rapidly moving crane, either in longitudinal or cross traverse, and the 
forces ilu,. to acvi'h-ration and retardation. Tin- horizontal longitudinal 
braking force shall be taken at not less than one-eighth of the load on the 
driving wheels and divided between the rails in proportion to the load 
carried by each. Tin- horizontal force due to the cross trawl of the 
loaded crab shall be taken at one-tenth of tin- weight of crab and load. 

(/') Provision shall be made for the forces due to the dragging weights along oi 

across the floor by means of the cranes, which shall be assumed to be 

a horizontal force at least equal to one-tenth «»f the lifting capacity of 
the crane 

(O The pull of belts and the weights of pulleys and shafting shall be taken 
as an additional load in hundredweights per lineal foot al least equal to 

-jr, where I» i- the 'liani.-t.Tnf the shaft in inches. It shall be assumed 
t'i act at an angle of L5 degrees. 

21. Tin- building shall be designed to resist anaverage steadj horizontal wind pressure 
of 30 lb. per square foot of exposed surface. This value shall be taken for all membei 
supporting an area of 300 square feet and under, and shall be diminished by 1 lb. pa 
square foot for each 100 square feet of area in excess of thisamount, but no value less 
than L'O lb. per square foot shall be used. 

One-third of the wind pressure only shall be assumed to act with the dead had and 
maximum live loads. 

22. A load of 5 lb. per square foot of horizontal projection shall be all-wed for on 
all surfaces where snow can collect. The snow load .shall be taken in addition to the 
wind load. 

23. No root shall be designed for a less load than 28 lb. per square foot of horizontal 
projection for a glazed or sheeted roof and 35 lb. for a slated roof. 

The roof loads shall he taken at the following weight- per square foot of hori- 
zontal projection : — 



S 






WORKSHOP MriLDFNYjs. 



Glcused Covering. 

Dead Load. 

i-in. rough casl glass 

Astragals ... 
Putty Fill,. is 
Purlins 



I Occasional Loads, 



Total dead load 



801b. wind pressure, Vertical compone 



Si 



|o\V 



lupoiieiit 



. . . 



Gahvmaed Corrugated Iron Covering. 
Dead Load 

No. 18 W.G. galvanised corrugated sheeting 

Rivets and strap- 
Purlins 

T«.tal dead load 
1 f ccasionaJ Loads. 

301b. wind pressure. Vertical component 
Snow 

Slates on Boarding. 

Dead Load. 

Slating, 16 in. x 8 in. 

Felt 

Boarding, 1 in. thick 
Purlins 



■ i • 



I'"tal dead load 



Vertical componenl 



Occasional Loads, 

30 lb. wind pressure. 
Snow 

Tiles or Slates on L Laths. 
Dead Load. 

Slating, 24 in. x 12 in. 

Lead nails .. 

Purlins 



'I'-.tal dead load 
' Occasional Loads. 

30 lb. wind pic— in.'. Vertical component 
Snow 



4.55 



lb. 

3.60 

175 

0.50 

2.00 

7.75 

20.00 
5.00 



Ik 
2.66 
1.20 

2.00 

5. si; 

20.00 
5.00 



lb. 
5.60 

0.25 
3.50 

.3.25 

12.60 

L'O.IIII 
5.00 



11.. 

9.00 
0.25 

LOO 

1 3. 25 

20.00 
5.00 



«8 



>"V 



i 






456 



WORKSHOP BUILDINGS. 











I reneral. 



Tensile 
Stresset 



< !ompressh e 
Stresses. 



Shearing 

Stresses. 



Bearing and 
Bending 

Strews. 



i Combined 
Bending and 
Direi i 

Stirpes, 



AVoi(ivi\«. S||!]-:sses. 

l'J. In no case shall the stresses under an j combination of loads exceed three-quarters 
of tli«- clastic limit of tin- material, noi be greater than the following values : 

•_'"). The tensile stress on the net section shall not rxcnl the following limits:— 

For live loads ! of the ultimate strength = 6 tons per square inch. 

For dead loads J ditto = 7£ ditto 

For wind and 

snow loads J ditto =10 ditto 

The total sectional area of a membei -hail be the sum of the areas required for 
each of the different loadings enumerated above. 

26. The compressive stress on the gross section shall nol be greater than 85 per cent, 
of the corresponding tensile -in—, nor be more than th.- ratio -iv.-n by Fidler's tab] 

for compression members. The top I ms of crane girders shall l fsufficienl width to 

resisl the forces from the cross trawl of the crabs or from dragging weights. The 

maximum unit stress shall be limited to a Han-' whose width is less thai i-twentieth of 

its length; where the Han- is less in width than one-twentieth oi its length, the stress 

snaU be ""educed by g ton per square inch for each u use in length of fivi times the 

width. 

No member in compression shall have a greater length than forty-five times 
its least width., or 120 times its leasl radius of gyration. 

Man. columns shall have a length nol exceeding fort} times their least width, and 
preferably one-twenty-fifth. 

27. The shearing stress on web plates of girders shall not exceed one-half of the per- 
missible tensile stress, and the web plate shall have stiffeners at the bearings, and al 
al1 1 lts ol concentrated loading, and at intermediate points, not further apart than 

T 

the depth of the girder, where the stress in tons per smiar- inch exceeds u- «,i , 

u i i- 3000 

II - the distance between flange angles or tiffeners divided by the thickness of the 

web plate, and T = the permissible unit tensile stress in the girder. 

The shearing stress on rivet- or turned bolt* of a driving fit shall not .-.x — 1 „- 
eighths ol the permissible tensile stress in the ca f plate girders and three-quai 

m the case of lattice girders. For black holts th, number shall be increased by 25 
per cent. 

28. The bearing or bending stress on rivets or turned bolts of a driving in shall nol 

""";""' """,'""' * -'J'"""-'' """- *e permissible tensile stress in the case of plal 

girders, and one and a-half times in the ease of lattice girders. For black bolts .1 
number shall be increased by 25 pur cent 

29. Where members are subject to combined bending and direct stress they shall be 

'"'"'"""•""■' , f '"' ""• ^'•'"'■'"" -'»' of the -, and the permissible stresses , 

'" '-— ..I bj 10 per cent The members shall be considered as partiallj continuous, 

;'"V "' T ":"" ; "'" '' , " : ' 1 '" ""■ ''" : """ "' "'" ''"'■ « U* ""■>'''»■' " 

■ ~""-"- 1 ben<iing moment at the ends shall be assumed to be equal, 

inn opposite to that in the centre 





LVS 



WORKSHOP JU'ILDINOS. 



457 



Masonry. 



Minimum 



I- ing B 



Tie Pl&tea 



30. The maximum prewures under the dead and Uve loads in masonry shall not 
exceed the following limits: — 






* rranite bedstones 

Limestone ditto ... 

Sandstone ditto ... 
*Ashlai raasour) in cement 
*Coursed rubble ditto 
•Random rubble ditto 
♦Brindled bricks in cement mortar 

Cement concrete ... 
*Stock brickwork in cement mortar 
* 1 >itto in lime raortar 



. . . 



• . . 



< 1 1 



. * . 



25 tons per square foot. 

20 ditto 

16 ditto 

1 5 pel cent less 

30 

60 

10 tons per square foot. 

10 ditto 

c. ditto 

4 ditto 



n 



Under the dead ana live load and wind pressure the permissible pressures may 
be increased by 25 per cent. 

♦ ?„ ««•«.— This pressure shall be allowed where the height is nol greater 
than twelve lames the width. 

Structural Details. 
SI Where direel stress is transmitted no steel shape shall weigh Ires than 4 lb. 
,„.,. ,,„;,,, ,„.„ ,„„. be less m width than '1\ in.; uor shall any structure! member, 

,,.;',,,,:,;,,, .-..I,,,, U lin Where the steelwork i- -„>,. -;— 

!,„„,., Iditionof h in. shall be made to the thickness, or a correspond^ , 

less than th, U — The die ft the, *****J ^ te „>,, 

„,., ,„. ,,... „,:„■ one an,l a-half diameters. At the .end, oi '- ^ 

equal twice the width of .1 lumn the pitch oi rrvets **£££ „ „„.. 

slaU dh tere. The thickness of metal in compress . *dl «rf be lore ^ 

ae.-i.tli of the .Stance between supports ... «.e line ^ .^ ^ ^^ ^ lcss 

:, ,,.=, n . i - ;■■•; ; ; ": ::rij:' ";:,:::■'."■' 

and double lattice bare connected by a rivet ai . X he width of the lattice bars 

,, Ulll „. ,„,„,.,,, the rivets connecting than to the . - • ^ ^ ^ , ll;in one . 

, !:ill „„ t be lesa „,,,, 3 diameters of the ,„,-,-'" " ^ r „ The 

eighth of the length of the bar. Angle bar taewg * ml '« - fc ? bj .„„.„„.,„ ri vets 

ing Lars stall be connected to the maw shafts w ,.,„,„,.,.„ ,!„■ lam.- l-ars 

todevelo, Lr strength. ^^TjJJ'L „<- ted 

-hall nol « I eight times the leas. w..ltl. »1 - tlir( .,,,,ar.,..- 

33. Where tie plates are I they ^^JS&l of oue-nftietb of *e 

of the width or de, I the col m and a ... nte of ,, ie „,„„, 

.1,- between the line of rivete -"f? 1 'J ' .'^ ol ,,,, tie plate, the ttacta 

Where stiffening angles are used on the '" " 

,.i\ I ie reduced. 



3 N 



re 



i 



gLo- 



».* 



3«S' 




.^>*v 



?HE 



458 



WnRKSHOr BUILDINGS. 



JoijiT- 






Riveted 
( Sonnections. 



I 'urlins. 



Roof Trusses. 



Ri "»t I rip lers, 



I ineGirders. 











< Columns. 



34. All joints shall be fully covered to transmit the loads as a shearing Btress through 
the rivets. Cover plates shall have an area of at least 25 per cent, in excess of the section 
joined. 

35. Hie rivet area shall l»- sufficient to develop the full strength of the hi-hiLt and 
at least two rivet- shall It used in making connections, or one rivet in double 
shear, notwithstanding that the calculated stress may require less. 

•"?<;. All purlins shall be made of -imp]-' -hap.--, desig 1 as semi-continuous beams 

and having a depth of not less than one-fortieth of their span. Thej -hall be placed 
over the panel points of the roof trusses, otherwise the bending stress in the raftei 
musl !"■ provided for. Provision shall be made for the expansion of long lines of 
purlins by loosely bolting some of the joints. 

37. All roof trusses -hall be constructed of rigid members capable of resisting tension 
or compression, and shall nave a depth of not less than one-fourth --f the -pan, A camber 
"fat least 1 in. for every JO ft. in length shall be given to all trusses. 

Where there are travelling or jib cranes in a bay, tie' horizontal ti«- ..f tin- r....f trusses 
between the columns shall generally be composed of two angle-bars, 30 as to act to 
some extent as a coinpre sit m member. 

Where shafting is supported from the roof-trusses the horizontal tie shall be con- 
structed of suitable sections to permit of the shafting brackets or hangers being attached to it. 

The trusses shall be rigidly secured to the columns by means of triangular brackets oi 
knee braces. 

38. Roof girders shall, as far as practicable, be of lattice construction with rigid 
members, and of ample depth to assist in bracing the shop either longitudinally or 
transversely. They shall preferably be placed Let ween the main minimi shafts and 
not over them. 

All girders over 40 ft. in length shall be given a camber of 4 in. for everv 
40 ft. in length. 

39. Crane girders shall generally! f plate construction, with a trough-shaped top 

l,;( "~" " f ;,,,! l' 1 " width (preferably one twenty-fifth of the length), and constructed to 
resist the vertical and lateral forces to which it may be subjected by the 'Tan-. 

The crane rail shall be riveted to the girder by rivets spaced about 18 in. alternate 
pitch. Bridge rails shall generally be used of the following weights:— For cranes up 
'_" -•' tons opacity a rail weighing 56 lb. per yard shall be used; for cranes up to 
50 tons capacity a rail weighing 70 II, per yard shall be used; and for cranes up 
to 100 tons capacity a rail weighing 106 lb. per yard shall be used. The rails shall 
not be included in the sectional area of the top flange. 

The .-nd plate shall be riveted t • end of the girder only, and provision 

made for bolting the abutting ends of the girders together by bolts spaced oot more 
than 12 in. apart. 

All girders shall be hutted hard, end to end, and no provision made for expansion. 
No camber shall be given to plate-webbed crane girders. 

•"• Columns shall preferably be constructed so that a shaft is provided under each 
girder, but where the girders are carried by cantilevei brackets from the columns the 
resulting bending stress shall be provided for. 





•A 



Workshop BUILDING. 



459 



Framing foi 

Sheetu 



Diagonal 
Bracing. 



\ i nti 



Weathei 
B Arding, 

Timbei 

i 



Steel Framing 

; ' It- 
work. 



') U ^"'""^ "' , " 1 """" connected by latticing shall have intermediate tie plates 
spaced doI farther apart than Bve times the width of the column. The tie plates 
shall have a depth oJ nol less than three-quarters the width of the column. 

The long dimension of the base shall preferably be placed across the shop to assist the 
ibility oi the building. 

All columns shall be secured to the concrete foundations by anchor bolts, placed 
,i- tar apart as possible so as to facilitate the erection of the shops. 

41. The framing tor supporting the corrugated sheeting shall generally be constructed 
oi "iir or more horizontal lattice girders supported at the main columns, with intermediate 
horizontal angle bars supported at points not less than 7 ft. apart by vertical angle bare 
or girders fixed between the horizontal lattice girders. 

Thf horizontal blades «>f the sheeting angles and girders shall be placed uppermosl i<> 
support ili'- h""k holts carrying the corrugated sheeting. 

4'2. Regard inu-t be had in tin- design "f the shops for the horizontal forces from the 
travelling jib and mono cranes, and from shafting or wind pressure. Shop.- over 20 ft. in 
height t<> tin- eaves -hall have suitable diagonal bracing in a horizontal plane placed 
between the tops of the columns and secured to tin- roof ties t" distribute the local 
forces from wind and cranes and to line and square up the building. To prevent tin- 
roof trusses being overturned bj end wind pressure on the gables, the pair of roof trusses 
.ii each ''iid shall be braced together between the rafters and in a vertical plane « 
the centre line. Vertical diagonal bracing -hall he placed between tin- main columns 
in the sides and ends "f tin- building to tab- up the horizontal forces due to cranes 
oi wind pressure. Where there an- deep roof girders this bracing may be omitted. 

43. Unless otherwise specified a continuous ventilator shall be provided only on the 
ridge of each roof. It -hall he constructed with curved flashings at the top of the 
ioof slopes, bo that, as far as practicable, driving rain and -now will he kept out. 

44. The weather hoarding shall have an average thickness of J in., laid horizontally so 
... lap ..vrr cad, other at least j in. The maximum span ha this boarding shall I- 5 ft 

45. The framing for carrying the weather boarding shall consistof main horizontal 
timbers, trussed if necessary, between the columns, and spaced from 5 ft. to 10 ft apart, 

cording to circumsfc s. Vertical timbers spaced not more than o ft apart ., ail 

be placed between , ,„. Ill;mi horizontal timbers and let into them ah.-ut £ m. at cadi en. . 
The depth of timber beams shall not be less than one-thirtieth of then- span 



Ml 



46. The, I ft ing far brickwork .hall be for "^-^fitotat 

joist* be ,,,!„,,, They e be pi, 1 soft, the I -•'',,,,,,,,,,,,,,,,',,, 

I i» area. Groutiw holes shall be provided in the webs of » 



Gates 



1 

j 

routing up the brickwork. 

-,it nine and hum? by anti-friction pulleys 
47. All gates shall be placed outside the ^^^^ ' 
from a suitable top runner secured to the framewor or .^ ^ i;l]1 be provided 

A cast-iron bottom guide of suitable section beddea ^ ^ 

act the opening a1 the floor Level, and extending each sid. 

full travel of the leaves of the gate. 



!** ^** 



460 



workshop building-s, 



I'ultN 
< ill/Ill'.'. 




I '■ ■ t ■ • I 1 t 

' Hazing. 



I rrugato <l 
Sheeting-. 



The gates shall be at least I in. wider and 2 in. higher than the clear opening 
and -hall I- made in two [eaves when the opening i- over 10 it. One him 
wicket -a!'', 6 ft. by 2 It., opening outwards, shall 1m- provided in all gates. 

A I I formed of J-in. steel plate shall be provided over gate opening I'm 

weather protection, ami shall extend at leasl G in. each side of the opening 

Karl, gate -hall be provided with a bolt, latch and padlock to secure the 1' 
and a suitable Lock fitted to tin- wicket. 

Th.- gates -hall generally be made of dressed red pine, framed with Mil.-- and 
rails, and lined with -in. boarding, and shall nol be less in thickness than •_", in. for 
gate- \-2\ ft. Mjuaiv, :3 in. l'. .]■ ^.t.-s 20 ft. square, and 3J in. for gates 25 ft. square. 

Where >.<•<•! gates are specified, thej -hall 1..- made of braced angle frames and 
covered with galvanised corrugated iron of th- -an,- gauge a- thai used on th- buildi 
'"' ''"• plating. Where the gates are in two leaves, one of th- leaves -hall liave 
,,; " ~"'l' riveted on th- meeting rail, so a- to cover th- other leaf when th- gate 
closed. 

Th- main framing angles -hall uot be less than 2^ in. by i", in. by ] in. for 
ites in ft. square, 2| in. by 2J in. bj ,-;.. in. for gates 15 ft. square, :< in. by 3 in. by J in. 
I " 1 ' 8» tea -° '''• square, :>\ in. ty :\\ in. U ,-, in. fa gates 25 it. square. 

Gates over 25 ft square shall be supported upon th- bottom runners and provided 
with suitable hand-operating mechanism. 

Where lifting gates are specified they shall Ik- provided with suitable counter-balai 
weights, chains, pulleys and guides, ami hand-operating gear. 

18. Th- glazing -hall be of th- quality and thickness specified in panes of the 
dimensions given. Th- edges an. I foi J in. in on both faces -hall be painted with 
l" ,|v white-lead paint, and -hall be dry before glazing. Th- sheets -hall la,, at lea 
- m - over '• ; "" 1 ' " ,1 '"'- ■" '•"■ ends, and the lap- -hall generally be over th- purl..,. The 

^ ass shaIJ ,je 2 '"• less in width than th- centres of the astragals or glazing bars. Hardv I 

pins, $ in. in diameter and 1 in. long, -hall be supplied and fixed through th- astragals. A 
I" 11 shaL be l' 1 "'"' 1 •" '•"• ends of each bar, at each la,, of th- glazing, and in the 
each sheet. Two /in- hooks or tingles, J in. broad U No. 13 zinc gauge in thickn -hall 
be supplied and fixed in th.- putty fillet at each lap. 

Th- tee astragals and putt} fillets shall receive two coats of pure white-lead pain! on 
the outside after glazing. 

Notb.— In tin- -ummer tin,- th- glass ... th- roofs may be painted with a mixture of 
™" l,,;, ; K ,l1 " 1 - and turpentin.- to ..hscuiv th- ,1a-, Sufficienl white lead is used to 
11l,rl 7' ""• ,1 ""'- ^d turpentine. If this mixture is pul .... in the beginning of summer, 
U ' vy ,lttle ! ~ lefl ''> ,1 '" " l " 1 - ^d i- easily cemoved l. washing with -...la ami water. 

49. Where patent glazing is specified, it shall he fixed in accordance with thi 
specifications of the makers. 

50. The side laps -hall be on,- corrugation and the -ml laps at leasl 6 in. Th- side 
111 , sl,a11 ,;IVr bolts i i"- ''" diametei and spaced not more than 24 in. apart. The 
"r . *1 ^ haVe boIfcs * '"• '" ^meter spaced ..... more than 6 in. apart alternate 
pitch. Lead or other approved washers -hall be placed under all heads or nut- of bolt 
"" »« outsides ... sheets. All nuts and bolts shall be galvanised and placed in the ridge 
ot the corrugations. 









•i 









fc«Ta» 







WORKSHOP BUILDINGS 



461 






G Ivanised 
[ron Flash- 
ings. 

.'anised 



SkewTimljem 



Slating. 



Gtittera and 



h..« 



nplpr-v. 



«•!,„. -I„.,ti„, b „.,i on the ventilator* i. sl,„n ,„, „„ :ltlv „,„,.,, „, ^ 
showo on the drawings. 

The sheeting shall be securely fixed to the purlins ] IV Ulk ll(llts « -, . 
";"'":'"'■ « b 3 -'-''-'J *■*■ I '-, In breadth by A in. in thickness, orb, ^vaiused 
clip. | m. .n breadth bj J „,. m thickness. The honk bolte, straps or dips shall nol be 
more than 1,> m. apart. The clips shall be fixed to the sheeting by ffo. 2 bolts 4 In. 
in diameter. 

The sheeting for side and end covering shall be fixed to the horizontal sheeting angles 
or girders by hook bolts ^ in. in diameter, spaced not more than 15 i... apart. The 
horizontal Made- <,i the -1 ting angles shall be uppermost. 

Galvanised corragated sheeting, No. 16 W.G., shall haw corrugations 5 in. centres 
and \\ in. in depth. The laps, bolts, etc. shall be arranged as for N<>. 18 W.O. 

Where especially tight laps (joints) are specified, the edges of the sheets at the laps 
shall receive 8 coat of thick white lead, painted before th-v are l.rouyht toother, or. -tups 
of canvas soaked in white lead may be inserted before closing up the sheets. 

51. Galvanised iron Bashings at ventilators and skews shall be made from plain 
sheets, No. 16 W.G. in thickness. 

52. Galvanised iron ridge pieces shall be made from plain sheets No. 16 W.G. in 
thickness, and shall not be less than 18 in. in girth, and shall lap at least 6 in, 

Where the roof is covered with corrugated iron the ridge piece shall be fixed to the 
corrugated iron by bolts \ in. in diameter, spaced not more than 10 in. apart. 

Where the roof is covered by puny glazing, the ridge pieces shall be fixed to the 
tee astragals by l ";.,-in. diameter eye holts. The space between the ridge piece and 

the glass shall be filled in by a w I strip U in. square, secured to the ridge piece by 

No. 2 wood screws. 

53. skew timbers about G in. broad by 2 in. thick shall be secured to the purlins by 
Its] in. in diameter sunk into the timber. The galvanised skew sheeting shall be secured 

to the timbers by wood screws with raised heads, spaced about 12 in. apart alternately. 
Li ad or other approved washers shall be used under the heads of all screws. 

54. Whee slating is speciiied the dates shall prcierahly be 24 in. by 12 in., laid 
with a 3-iiL lap, and securely fastened to the steel L purlins byNo.21ead amis, * in. 
square in each slate, benl round the purlin, or by two No. 14 gauge copper wires placed 
through each slate and secured round the purlin. 

Double slates shall be put in at the eaves and ridges. 

The slat- shall be properly sorted and squared, and the vertical jomt shall I pa cm. 

line from the eaves to the ridge. 

55. The gutter, -I ,e le fron, J-in. etamped ,.,-1 pktota '^J*'^* 

The joinfa -l„ll be , le with a 4-i„ faj J-in. outer • , plate. A >., ** « ■ 

,ked in red lead shall be ineerted between gutter 1 eover to make a thoroughly wete 

" u1 '' •'"'"'• , i-i u «•• id in between the glass 

va..ey gutters shai. i, at least it .,,. i -';7 1,h ; ;;;; 1 ; ,,< ;..; ,„,.„„ ** a. 

or sheeting. Eave gutters shall beat least 12 m. m widtn. m 
niininiuiii space for a man to walk along the -utters. 

The gutters shall preferably have a fall of 1 in. "> ,i0 ft " 



& 






*E& 



y< 



462 



WORKSHOP BUILDINfJS. 



Roof Gang- 
ways ;unl 
Snnw Board- 
ing. 



Roof LaddfiN. 





Brickwork. 















The down pipes shalJ be proportioned so thai thej shaU have an area of at least 
\ square inch for every 100 square feet of roof surface drained. 

The down pipes shall be of cast iron and secured bo the covering by suitable holdfasts. 
The joints shall be caulked with red lead and hemp. 

50. Gangways shall be at least 18 in. wide, and shall be made of 3 in. by 1 in. ,-,, 
boards laid with 1 in. spaces upon 2 in, by 2 in. Longitudinal runners. The runner on 
the rool slope shall have a 5 in, by 1 in, baffle board nailed to it and supported on the 
astragals. 

The outer longitudinal runner shall be secured to a ->\ in. by 24 in by | in angle 
by 8 in. diameter bolts 2 ft. 6 in, piteh. The 2J in. l,y"2J i,, l, v \ in. longitudinal 
runner shall be carried by 2j in. U 2j in. by | in, angle standards spaced not more 

than 10 It. apart. 

On the eaves gangway a suitable handrail shall be fixed about 2 ft. in. above 
the gangway level. 

All gangways shall be made in convenient lengths to allow them beins lifted foi 
cleaning the gutters. 

The gangways on roof slopes shall be formed of two sawn pine timbers 6 in wide 
by _ >n. thick, and supported on the astragals at points not farther than 6 ft. apart. 

, 57 R "" f Wdan ~ ,i;i11 '"• ab0 ^ 12 in. in width, and be made of two sawn boards of 
"<' Pine 6m wide by I J in. thick, laid with] in. space and supported upon the tee 
astragals by red-pine cross bars, 2 in. square by 5 ft. long, spaced about 7'. ft. apart. The 

tlV; ; ,h >l,;l11 ,,r l in " -1" ; "'" and -'""'«' I2in. apart. Two wl 1. not less than 1 in 

m^ameter and 5 ft. centres, shall 1,- provided at the bottom cross bar to run upon the 
Dame board <>f the roof gangways. 

58. Dwarf brick wall. ,hall be generally 5 ft. high above Hoot tine and 9 in. or 14 in. 

"> thickness. Il„. minimum thickness shall be need where no pressure IV the -,l. 

•■■ -v.-i in- !- earned by the wall. 

I'-.v course shall be l.,,|,|,.,| i„ „„„,,,. aI11 , thoroughly grouted with thin mortar 
u . I ever, ,„„ . thoroughly l,ll,.| before the next course is laid. Ever, fourth cou, 
of thewalls shall be a header , ,,. No joint shall ,xc * in. in ,|,i.W 

enl "l"n '"'• '" C W '"' k ^ ';'"" """ •""' ''■ "" Ik *''•• '"' i ' k - -'-" '"' "-«) 

"„ "'"■' .""" ';,' M "" hV " ll; ' md ""• S ' '"•'"'■"" °* **«* and brickwork 

nffl £' ^ bMCl 7° rk ** * bnil( ^y ^er the horizontal member 

;!, :/ ';;;J';' • ! " """'"" l up """"- 11 the Uoles «*"«•<« « a- -i.. i«,„k. ,,,,. 

tl.. waUatitehase. These dimensions shall not apply to dwarf walk 
Ihe height of walk shall be measured as follows- - 

1. Sid, wall- F,. m the base of wall to the underside of the , f truss. 

C.al.1, wall, i .,..,„ tt e ha.se of wall to half ,1, heighl of the gable. 
The bcjjht „f ., .,,„,,. s]ki h |i( . meMnred M f()]lowe ._ 

1. Topmosl ,torey. F,-„„, the underside of n„„r !..,„„- to the underside „f 
the tie oi roof truss. 

2 " 0thei ~"."7~- From ""• ^derside of floor joist to the undexside of floor 
joist ->t the storey above. 






^ 



workshop BUILDINGS. 



463 









In no ease shall the height of a wall, if there are no floors, or the height of a storey, 
exceed fourteen times tin- thickness of the wall, where an external vertical load ia carried, or 
m sixteen times the thickness where no load is carried. Tin* increased thickness may be pro- 

vided for bj piers properly distributed, so that their collective widths equal one-fourth part 
of the length of the wall. 

In steel panelled construction the size of the panels shall not exceed 150 square feel 
in ar<a, nor -hall the thickness be less than one-twentieth of tin- maximum distance 
between the steel frames. 

The thickness of cross walls shall be two-thirds the thickness of external walls, 
provided the openings do not exceed one half <>f the area ..f the wall. 

No cross wall shall be less than 8| in. in thickness. 

The length of a wall -hall be measured between the centres of return walls or 

CrOSS walls. 

Hull-..— 1 bricks shall be used al all jambs of gates or doors. 

59. Both sides of the brick walls -hall be thoroughly pointed and hard drawn with 
a square key in perfectly level and perpendicular lines. The whole of the brickwork 
shall be pointed as the work proceeds. 

D ,.r - CO. Ever, wall .1.11 have . dam, arse, com, 1 of material impemou. to 

„„„.,„„, extending throughout to whole thick . a level of ao. lee, than 6 n, 

i n i i ,. i Tin. il'iinn course niav 1«* omittm in rtwart \\aii>. 

above tin* ground level. Lne oamp toura maj 

6 ] Where timber covering is used above the dwarf wall the wall jlate ahaU be 

t ,i wn ll m,l securelv fixed t«> the wall by bolts ; in. 

huh } in. in diameter. 

Slowest *e of f oothy I *.*j J- * **££ '„,„., snS e the 

f the concrete to allow for any inequalities in ^ ^ ^ ( ,„,,. ,„. 

concrete to break across through unequal * ttle " e ™\ reinforced with steel rode. 
. |han ,,,„. iu thickness. Where necessary, it shall 



Timber Wall 
Plates, 



Foundation* 
Undei Walls, 



Foundations 
I rnder 
Columns 



Foundation 

Holts. 



<»• !*• '•'""•'""" f»« nd »» i0M " l " 1 "' ^^ckn^ahThe^UeaTone-thhu of the 

round than the base plate of t '"' »'"' '"' ' ' toeqm mies in the foundation. 

„„*„„„,„ dhnenaioi, of the concrete to allow for W J^^ 

1 u it^ra^ssi 3- u. . < .- 

- •».— •** » - t -- n " , " i ; i 7 , ;\,, 11 1 .. fcftiIltI ,,,,• 

64. In ordinary « hoi dewit. ^^ fte ,* i. set.) The 

the foundation bolts. (The w len boxes are ** ,„. ,j in . i„ dnuneter, 

holes shall be U in. < *• * .^2£.«l* wL, 6 in. square b, J» 

with a square ,1, and -J ft in length,™* •«*£ Ld the «*e de, ted , ad 

thick TheyahaUbe eel in position " .^ eveM ; ,„,l set. 

them, and ahaU be grouted up when the column n 









A 



-^A 






m 



<: 



Temperature 



\\ orkman 
ship. 



4C4 



WoifKsnoi- BUILDINGS 



On.- inch shall be allowed between the top of the concrete and the underside of the 
column liase for grouting up when tin- columns are sel in their correcl positions. 

65. Nn special provision shall 1>*' made for expansion ->i contraction in the length or 
width of ili.- building if it i- of st.-r-l framed construction throughout, excepl in the 
purlins of a glazed roof, where ample provision is made by bolting the joints about 
ever? 3d ft. Where the trusses real on brick or masonry walls slotted holes -hall be 
provided in tin- trusses in spans over 60ft. and in the purlins and roof covering at 
id-' rate of .1 in. for t*v«rv 100 it. in length. 

GO. Tin- whole of the workmanship -hall be <>f a first-class character throughout 
and ti ue to dimensions. 

All sheared edges -hall be planed <t machined where stress is transmitted, and all 
holes in girders and columns and in thicknesses -I' g in. and over -hall be drilled. 

Machine riveting shall be used wherever practicable, and all connections at the 
site shall be bolted. 























( 465 ) 



Index. 






>u 



s,, 



Aggregates In Concrete in Coated with Steel or 

[ron, 412 
yisa Shipbuilding Company's Workshops, 142 
An. Compressed, Planl for Foundations, 275. See 

is. L9, 47. 70, 98 
Air-Locks for Bridge Pies Foundations, '277. 

is. L9, 47. 70, 98 
Air-Plan( al Dalmarnock Works, 54 
Uexander III Bridge, Paris, Foundations, 396 
Alloy-,,! Metals, Properties of , 414: Weights, 416 
Alma Concrete Bridge, Paris, 60 
America, Wind Pressure on Buildings in, 388 
Angle-Cutting for Girders, 38, 259 
Approximate Weight of Travelling Cranes, 381 
Arch Bridge, Clifton, America, Foundations, 397 
\\xh Bridge, Edinburgh, 123 
Areas oi Sections, 346-363 
Armstrong's Workshops, 24 
Axrol and Co., Sir W., Workshops, 142 
Avon sum,- Bridge, Bristol, Foundations, 397 

BabcocH and Wilcox Workshops, 24, L42, 188 
Hall Bearings, Calculations for, 375 
Barclay, Curie and Co. 'a Workshops, 14'-' 

Bar Cutting for Girders, 38, 259 
Barr and Stroud's Workshops, 142 

Bascule Bridge, Tower, London, 2, 1". U, 64,87, 

396 
Beam Curved ; Boat Davit. 2S<> 
Beams, Formufceand Diagrams for the Calculation 

of, 281 
Beams, etc., Formula for Moment of Inertia, 

Radius of Gyration, etc., of, 345 
Beams, [nclined, Special Cases, 306 
Beams of Solid Cross Section, Formula and Dia- 
grams for I 'al.nlatioll. 364 
Beardmore's Engine Si. , v >. •_':$, -'4. 142, 15" 
Bearing Pressures, Formulae and Diagrams for 

< lalculal ing, 376 
Bearings, Calculations for, 374-375 
I '»»"_' urn ii i<_; nf Airol'a Works, 2 
In^iimiim of Girder Work, 4 
Bending, Cross, and Duvet Tension or Compression 

(Combined Stresses), OdeuJatioiifl for, 371 
Bending Moment Diagrams and Formula tor 

Beams, 281 



Berth, Shipbuilding, Beardmore's. 17)11 

Berth, Shipbuilding Harland and Wolffs, 160 v 

Black friars Bridge Widening, London, 136 \, 412 

Blackfriars Railway Bridge. London, 397 

Boiler-making, 3 

B tiler, Pressure on Shell of, 393 

Boiler Shop at Beardmore's Works. 154 

Boiler-Shop Cranes, 219 

Boiler Shop, Fairfield, 167 

Boiler Shops, Marshall's, Gainsborough, 202 

Boiler Works, Babcockand Wilcox. 188 

Boiler Works, D. Rowan and Co., L90 

Boiler Works, Poplar, Yarrow's, 178 

Boiler Works, Scotstoun, yarrow's, 184 

Boiler Works, Wallsend Slipway Company's, 174 

Boilers at Dalmarnock Works. 50 

Bolts in Masonry, Holding Power of, 407 

Bothwell Viaduct, 4, 5, <54 

linw Kleetric Generating Station. "20. 142 

P.racinu-. Portal, Diagrams and Formulas tor < alcu- 

lating, 332 

Brass Shop at Dalmarnock Works. 4'.'. 50 

Brewery Stores, (iuinness. 206 
Brick Piers, Strength of, 406 

Bricks, Tensile Stress to Separate, 410 

Brickwork, Strength of. 404 

Bridge Building, 57, 136 
Bridge Foundations, 39« 
Bridge, Ruhvay, Specification Jor, 428 

-'''^-Tirs-V't;:::;:/;^-- >- 

Bridges Built DJ su n. o 
sions, etc., 64-65 

Bridge Designed i.y^.-i^-- 2 ^ 

Bi klyn Bridge, 62 ^ Workshops, 24, 

Brown and Co. 8, J-i J 

14*2, 140 ...... 

BudaPes^BrKteeom^^ 130f211 

Build e re and Designers of Bndg ., () 




*> 












4<;i; 



INDEX. 



Building Roller Lifl Span, 47 
Buildings, Expansion and Contraction of Steel, 39] 
Buildings, Superimposed Loads on Floors of, 41l* 
I (uildings, Tn.it menl of Portal Action on Steel 
I Mill, 33» 
I '»um\ ancy, 4'»;i 

Cabin -John Liritlge, Washington Aqueduct, 60 

Cairo, Bridges over the Nile, 17. 22, 38, 64, 93 

Caisson, Building for Foundations, 4«J 

Caissons for Forth Bridge Foundations, 7". 71. 396 

Caissons, Lowering Bridge, 136b 

Caissons lor Wear Bridge, 98 

Calculation of Beams, Formula ami Diagrams for, 
281 

Caledonian Railway Bridge, Glasgow, •_'. I. 17. ii4. 

115, 397 
Cammell Lairdand Co.'s Workshops, 24, 145, 161 
Campanile Tower, Cremona, Foundations, .".!»7 
Canal Bridge, Sum-. 128 

Cantilever Ann- «>f Forth Bridge, 74, 7.~> 
Cantilever Bridge, Dalginross, Comrie, 130 

Cantilever Bridge (Forth). >>, s. !», 17. 46, 64, 66, 
396 

Cantilever Cranes, Revised Specification forHeavv 
419 

Cantilever-Erecting System fox Wear Bridge Span, 
99 

Cantilever Loads on Beams, Formuheand Diagrams 

of. 281 

Cantilevers, Inclined, Formula and Diagrams for 

Calculation, 306 

Carlisle Citadel Railway Station, 142 
Carpet Factory, Templeton's, 26, 145 

1 last-Iron Bridges, 61 

Cement and Concrete, Strength of, 4**7 

Chambers, Air. for Foundations, l'77 See is ->l 
7<», 98 

Charging Machinery, Gas Retort, 233, 235 

Charing Cross and City Electric C pany's Station 

26, 142, 14:;. 204 

Charing Cross (London) Bridge. Foundations, 397 
Chimney stack. Guinness's, 208 
Chimney, Wind pressures on, 388 
Cleaning Machinery, Gas Retort, 238 

Clifton And. Bridge. America, Foundations, 397 ' 
CI. ft on Bridge. Hi' 

Clyde, Caledonian Railway Bridge over ° 4 r 
64, 115, 397 ' ' ' 

Clyde Shipbuilding Company's Workshops, 142 

Clydebank Works Buildings, 14t; 

Clydebank STard Crane Foundations, 18, 21 396 



c«.al Elevating and Conveying Plant, 242 
Coal Stores, Glasgow Corporation. 143 
I !i talbrookdale I Iridge. <>1 

Column Bases on Different Levels, Portals with 

337 
Columns with Eccentric Loads, Diagrams and 

Formula for < lalculating, 326 
Columns, Fixed, Portals with, 336 
Columns Hinged al Base, Portals with, 333 
Columns Supporting Roof, Diagrams and Formulae 

for Calculating, 337 
Columns, Ultimate Strength, 340 

Combined Stresses of Beams, etc., Calculations for 

.571 

Competition in Bridge I >. -ign, -J2 

Compressed Air Plant for Foundations, 275. See 
18, L9, 47. 70, 98 

Compression or Tension, Direct, Cross-Bending, 
and (Combined Stresses), Calculations for, 371 

1 'olierete Uridine, I ill 

Concreteand Cement. Strength of, 407 

Concrete in Contact with Steelorlron, Aggregates 

of. 412 

Concrete Foundations. Loads, etc., on, 399 
" Constrained Cantilever " Bridge, at Comrie, 130 
Continuous Girders, Formulae and Diagrams for 
Calculation, 301 

Continuous Portals, Diagrams and Formulae for 
337 

Constructional Steelwork, 22, 139-208 
< on\va\ Bridge, «;i 

Conveying and Elevating Plant, Coal. 242 
iorrosion, Aggregates in Concrete in Contacl with 

Steel or Iron. 4Il' 
I lorrosion of Iron in Water, 410 
Corrugated Sheets, Calculations for, 373 
Counterweight, Weight ofKentiledge for, 411 
Coupling, Bydraulic Hose, 249 
Coventry Ordnance Works, 14.;. 168 
Crane, 150-Ton Iluimner-Head Elect ric, at Chde- 

bank Works, 260 
Cian.-. 150-Ton, Wallsend slipway Company's 

Foundation, ;i'.i7 
Crane Foundation at Clydebank, 397 
Crane Tracks in Workshops, 140 
Crane Wheel Loads. Distribution of, on Top 

Flanges of Gantrj I orders, 384 
Cranesat Dalmarnock Work., ;u. 42 

Cran.-s. Heavy Cantilever, Specification for Struc- 
tural Portion of, 419 
Cranes, Bydraulic, 216 
Cranes, Manufacture of Hydraulic, H 












n * 







fc&Sn 

























y. »• 






t * 






• 






INDKX 



46* 



Cranes, Shipyard Berth, ai Harland and Wolff's, 

Canes, Travelling, Approximate Weights of, 381 
s Pravelling, General Specification for Struc- 
, ul ,,l Steelwork, 422 
Cross Bending and Direct Tension or Compression 

i ombined Stresses), Calculations for, :'»71 
Crowds, Loads, on Floors of Buildings, 412 
Cylinders, Hollow, Stresses on, 393 

Dalginross Bridge at Comrie, L30 
Daimarnoek Works ai Glasgow, 27-56 
Davit, Boat, 286 
Decking of Bridges, 45. See 250 

Deficient Frames, 370 

Deflection of Framed Structures, Calculation of , 366 

Deflections of Beams and Cantilevers, 281-312 

Deformation, Elasl ic, 367 

Depths of Girders, Economical, 380 

Derricks for Shipbuilding Berths, Electric, 272 

D, of Workshops, 139 

Desi| • and Builders of Bridges, I, 59, L39, 211 

Designing Department at Works, 21, 35 

Diagrams and Formulas for the Calculation of 

Beams, --'81 
Dimensions of Bridges built by Sir W. Arrol and 

Co., 64, 65, 396 
Direct Tension or Compression, Cross Bending and 

(Combined Stresses), Calculations For, 371 
I inert m s o! Companj . 30 
Distribution of Electricity ai Dabnarnock Works, 

52 
Dolphins at Swing Span, Barrow Bridge, Ireland, 

109 
Dowrie and Co/a Workshops, 143 
Drainage, Roof, i'.'dO 
Drawing I offices, 36 

Drilling Machine and Bridge Building, -'• 4, 42 
Drills for Girder Work, 42, 4:; 
Dubs' Locomotive Shops, 24 
l tachemin's Formula, 389 
Dufferin Bridge, Benares, Foundations, 397 
Dunsmuir and Jackson's Workshops, L43 
Durability of Iron in Water, HO 

Earth Soils, etc., Weights of, 415 

Eccentric Loads, Diagrams and Formula for < al- 

culai ing, 344 
Ecteotiiraiiy- Loaded I Solnmns, 326 
Economical Depths of Girders, 380 
Economy of Manufacturing, 29, 32, 33, 56, 139,21 
Edinburgh Suburban Railway bridges, 4 



Effects <>f Temperature on Metallic Structures, 391 

Elastic Line, Equations to, 281-312 

Electric Derricks for Shipbuilding Berths, 272 

Electric Generating Station, 204 

Ekrtiic Hammer-Head 150-Ton Crane at Clydebank 

Works, 200 
Electric Light Station Buildings, 25 
Electric Power at Daimarnoek Works, 52 
Electrically-Driven Hydraulic Pumps, 21.*) 
Elevating and Conveying Plant, Coal, 242 
Engine Erecting shop. <;. and J. Weir's, 194 
Engine Pitting Shop, Setts', (Ireenock, 17<"» 
Engine Works, Cammell Laird and Co., l«>*. 
Engine Work-. Scotstoun, Yarrow's, 182 
Engine Works, Wallsend Slipway Company, 172 
Engineering Department at Work-, 5, 48 
Engineering Productions, Mechanical, 209-277 
Engineering Workshops and Boofa, 22, 139-208 
Erecting Departments at Daimarnoek Works, 30, 31, 

55 
Erecting New Redheugh Bridge Outside Old, 120 
Erecting Shop „f Engineering Department at 

Daimarnoek Works, 4* 

Erecting Weai Bridge Spans, 99 
Experience in Workshop Tools, -11 
Experiments, Friction, :*78 

Factory Buildings, Design of, 139 ^ 

Fact-ry Buildings for Guinness, 26, I U 2WS 
Fairfield Company's Workshops, L 43, 164 

Fenchurch Street Electric Sub-Stat 14- 

Fust Iron Bridge, <"»1 
First Notable Contract, 4 
First Workshop Roof Built, 22 
Firths Workshops, Sheffield, 143 
Fittings and Valves, Hydraulic, 24, 

Flanging Press, Hydraulic Pipe. -->J 
Flotation and stanuuy 

385 

Forge Cranes, 218 Calculation of 

Formulas and Diagrams ft* 

Beams, 281 Radius of (Jyw>- 

Formula* for M -» - .„«u.«. '-■»' ■ 

ti.n etc of Beams etc., a* 

Forth Bridge, 2, 8, »i «« 

:m - '"''"' i ( Wind Pressures, 387 
Forth Bridge, Record of ^«- 
Foundations, Concrete, 3 ds, 













4(18 



INDEX. 



1 






Foundations of Forth Bridge, 7<». 71. 396; Tay 
Bridge, 82, 396 

Foundations, Notes on, :;'.'•',. 398 

Foundations, Subaqueous, for Bridge Piers 17 46 
82, 98. 396 

Foundries. Ck-nrield and Kennedy's 171 
Foundry Buildingsal Victors' Works, L58 
Foundry, G. and .1. Weir's, 1!»4 
Framed Structures, Calculations for Deflection of 

Frames, Redundant, Calculations for, 370 
Freiberg Bridge, Switzerland, 61 
Friction Experiments, :;;s 
Friction of Hydraulic Rams, 394 
Friction, skin, in Foundations, 399 



Gantrj Girders, Distribution of Crane Wheel Loads 

"ii Top Flan-., of, 384 
Gantry (iird.Ts. Lateral Forces on Top Flanges of 

Gas Works Retorl .Machinery. 230 
German Chimneys, Wind Pressure on, 388 
Girder Building and Erection at Taj Bridge, 83, 
84j 85 

Girders, Continuous, Formula and Diagrams foi 

I alculation, :;<n 
Girders, Economical Depth, of, 380 
Girders with Panels, Bending Moment and Shearin, 

Force due to Wheel Loads. 321 
Girders with Sub-divided Panels, Stresses in 322 
Girders in Walls, Loads on, 380 
Glasgow Bridge Foundations, 397 
uiasgow, Caledonian Railway Bridge, 2 13 i:, r 
64, 115, 396 ° ' ' ' ' ' 

Glasgow Corporation Electric Station, 26, 143 
Glasgow, Dalmarnock Works, 27-56 
Glenfieldand Kennedy's Workshops, 24, 14;; 171 
Great Cenfral Railway, .Manl,bo„e, Warehouse 
Foundations, 397 

Great Northern Railway Company's Wood Stores 

Greatest Cantilever Bridge (Forth), 2, 8, 9 17 46 
64, 66, 396 * ' ' ' 

Grosvenor Bridge, over the Dee, Chester, 60 
Guin^sss Brewery Buudings and Stack, 26, 143, 

Gyration, Badius, Formal* for Beams, ete., 345 






Hall. Russell and Co.'s Workshops 143 

*■?»£*»*. 1^-Ton Electric Crane, at Clyde- 
bank AN-uk-. 260 

Hanover Timber Bridge 59 



ig 



•Mac! 



line, 259. 



.M 






Barbour Wharf Foundations, 17. 4»;. :;>.»; 
Harland and Wolff's Shipbuilding Berth, !»;<; \ 
Hawkesbury Bridge, Ne* South Wales, LO, 397 
Hawthorn, Leslie and Co.'s Workshops, L43 
Heat, Mechanical Force of, 392 
Heavies! liaseulu Bridge, Tower, Londou, 2 10 II 

64, 87, 396 
History of Bridges, 59 
Histon of Company, 1. 59, 139, 211 
lL.ldiii._r I ',,»,., f Bolts in Masonry, 4<>: 
Hollow Cylinders, Stresses on, 393 
Hose Coupling, Hydraulic, 249 
Howden and Co.'s Workshops, 14:; 
Hydraulic Angle and Bar-Cuttin 

See 38 
Hydraulic Cranes, ju; 

Hydraulic Jack, Portable, 256. See 4. •;. n:, 
Hydraulic Machine for Forming Knee Bars, el 

«>f Girders, 40, 41, 257 
Hydraulic Machines, Experience in, 211 
Hydraulic Motors, 244 

Hydraulic Pipe Flanging Press, 2.~.4 
Hydraulic Power a1 Dalmarnock Works, 53, 54 
Hydrauhc Pressure, Calculations for, 385 
Hydraulic Pumps, 212 
Hydraulic Lams. Friction of. :;'.i4 
Hydraulic Riveting Machines, l\ 6, 44. 223 
Hydraulic Stamping Press, 250, 252. See 4:. 
Hydraulic Valves and Fittings, 247 

Inclined Cantilevers a,,d Beams, Formula and 

Diagrams for Calculation, 306 
Inclined Surfaces, Pressure of Wind on, 389 
Wia, Moments of, Formuliefor Beams, etc., 345 
Influence Lines, Formulaa and Diagrams for l a- 

ti"ii of lieani^, ;U.S 

Invention and Bridge BuUding, 2, 59, 139, I'll 
Iron Bridges, 60 

Iron Coal Pier, at Norfolk, Va.. 39? 
Iron Durability in Water, 41"> 

Jack, Portable Hydraulic, 2:,.;. See 4. 6, 115 

Jacks, Hydraulic, f»r Kai.sing Bri.l^v li, 115, 256 
Jib Cranes, 216 

Jiggers for Shipbuilding Berths, Electric, 272 
Jones and Colver's Steel Work.. 143 

Kentiledge, Weight for Counterweight, 411 
Kilbowie, Canal Swing Bridge, 128 

Lanarkshire Steel Company's Building, 143 
Landore Timber Bridge. 69, 60 



t\r>F.x. 



469 



i ,._, ,. Timbei Bridge in Britain, 80 

Lateral Forces on Top Flanges of Gantry Girders, 

385 

Launching Girders, 4 

Leith Railway Station, 14+ 

Lighting oi Dalmarnock VV orks, 53 

Lime Mortar, Strength of, 410 

Limestone, Properties of, +1+. Weights, 416 

Lines, [nfluence, Formulae and Diagrams for Cal- 
culation, 318 

Loading of Beams, Formula- and Diagrams for 

Calculation, 28] 

Loads ' me Wheel) on Top Flanges of Gantry 
Girders, Distribution of, 384 

L,ad-. Eccentric, Diagrams and Formulaa for Cal- 
culating, 344 

Loads on Foundations, 396, 398 

Loads "ii Girders in Walls, 380 

Loads, Moving, Formulas and Diagrams for Cal- 
culation of Beams, 313 

Loads, Moving, on Panelled Girders, Calculation 
by [nfluence Lines, 321, 324 

Loads, Superimposed, on Floors of Buildings, 412 

Locks, Air. for Foundations, 277. See 18, 19, 20, 

21, 7>). 98 

Locomotive Shops, North British Locomotive Com- 
pany, L98 

London, Blackfriars Bridge, 136 a, 412 

London Bridge, 60 

London Bridge Foundations, 397 

Lond-n and Glasgow Shipbuilding Company's 

\\ orkshops, 144 
London and North-Weatern Railway Bridge over 

Manchester I lanal, 134 
London Tower Bridge, 2, 10, LI, »',4. 87, ■'•'■^ 
Loi Viaduct, 2. 8, 64, 79, 396 
Lmu. ion Brothers' Workshops, 144 
Lowering lhidge Caissons, L36 B 

MacFarlaiK. Lang and <Vs liiseuit Fact-ry. 26, 

144 
Machine and Erecting Department at Da I mar nock 

Works, 29 
Machine Shop at Beardmore'a Works, 154-157 

Machine Shop, Poplar, Farrow's, 178 
Marl,,,,,. Tools Designed for Forth Bridge, 70, 7<i 
Machine Tools, Experience in, 211 
Machinery for 150-Ton Crane, 269 
Machining Plates, etc., for Girders, 38 
Mackie and Baxter's Workshops, 144 
MacOnie's Sugar Engineering Shops, 144 
Manchester Ship Canal Bridges, 10, 64, 133 



Map Showing Site .if \Y.,rks, 3 

Marshall. Sons and Co.'a Workshops, ■-'+. 144. 202 

Martin. Millar and Millars' Lime Stoves, 144 
Masonry Bridges, 59 
Masonry, Bolding Power of Bolts in, 4i»7 
Masonry, Properties of, 414 ; Weights, 416 
Material Receiving Yard at Dahnarnock Works, 28 

Materials in Common Use, Properties of, 414; 

Weights, 415 
Mechanical Engineering Product inns, 209-277 
Mechanical Force of Heat, :'.'.»•_' 
Menai Straits bridge, 01 
Merchandise, Weighfcsof, 4lt; 
Metal Bridges, 60 

Metals. Mechanical Force of Heat. 392 
Metals. Properties of, 414 ; Weights, 41<i 
Metallic Structures, Effects of Temperature on, 391 
Metropolitan Electric Company's Station, 26, 144 
Mine Shafts. ( impressed- Air Plant for Sinking. 27.") 
Moment of Inertia of Beams, etc., Formula? for, 345 
Mortar, Lime, Strength «»f, 410 
Mortar Joint, Shearing Strength of, 404 
Motors. Electric, at Dahnarnock Works, 52 
Motors, Hydraulic. 244 

Moving Loads, Formula' and Diagrams for Calcula- 
tion of Ik-ains, 313 

Moving Loads on Panelled Girders, Calculation by 

[nfluence Lines. 321, 324 
Moulding Loft, Clydebank, 149 

Naval Engine shop of W. Beardmore and Co. 

Newburn' Steel Works Buildings, 26, 146, 200 
New York Bridges, 62 

Niagara Bridge. 62 

Nile Bridge, Cars, 17, 22, 38, 64, »3 

North Bridge, Edinburgh, 123 

N„rth British Company's Leith Railway Station, 

NorftBritish Locomotive Company's Workshops, 
No i^ritishBaawa T ,BothwellViaduct,4,o,64 

Offices of Company, 28 






ness, 



160 



Parallel Girder Bridges, 82 



"M 



s _', ••«, 396 



470 



IN' HEX. 



Piers of Forth Bridge, 72, 73, 74, 75, 396 
Piers for Foundations, ::!»<;. 398 

Piers, su-cl Trestle, Specification for Railway 

Hi -.. 43«.» 
Pins. Tors of lirick, 406 
Piles, Resistance in Sand, 4«ii> 
Piles, Timber, Loads on, 400 
Pipe Flanging Press, Hydraulic, l'.Vj 
Pipe Riveting Machine, 226 
Plan of Girder Machinery and Erecting Shop al 

Dalmarnock Works, 32, 33 
Planing Edges of Plates, 39 
Plates, Strength «.f. Calculations for, 372-374 
Pontoons, Stability and Flotation of Rectangular 
403 

Pontoons f.. r Tay I triage Erection, 82, 83 
Portable Hydraulic Jack, 256. Sei I. 6, 115 

Portable Kiv.inm -Uulmi,-. l\ 6, 41 223 

Portal Bracing, Diagrams and Formula foj Cal- 
culating, 332 
Pedestal Cranes, l'l'1 

Power Plant at Dalmarnock Works, 50-54 
Press, Hydraulic Stamping, 250, 252. See 45 I 

Press for Stamping Deck Plates for Bridges 45 
254 1 

Presses for Knee Bars, etc., of Girders, 4<». 41. 257 

Pressure, Water, Calculations for, 385 

Pressures on Bearings, Formulae and Diagrams for 

Calculating, 376 
Pressures, Wind, 386 

Principles Applied al Dalmarnock Works 29 59 
L39, I'll 

Problems in Bridge Design, 62 

Properties of Materia] in Common Use, 414 

Properties of Various Sections, 345-363 
Pumps, Hydraulic, 212 



Quay Wall Foundations, 17. 46, 396 

IWimd Gyration of, Formula, for Be 8 , etc., 

Railway Bridges, Specification for 4-7 

Railway Bridges, Index to Specifications for 425 

Kail way Bri.l^s, Sudan, 126 
Railway Goods Stores, 14:; 
Railway Station Roof, 142 144 

Raising CWedonian Bridge, Glasgow, 4, 6, 115. 

bee L'.»d 

Rams, Friction of Hydraulic, 394 
Ransomeand Rapier's Workshops, 144 

Ked ^5; Vd ' Tyne at ***** 2 > 1:: - 



Redundanl Frames, Calculations for, 370 
Regulations for Compressed-Air Work, 20 
Retori Machinery, Gas, 230 
Retrospect of Bridge Building, 59 
Resistance of Piles in Sand, 400 
Rest, Friction, 378 

Rings, Strength of, Calculations for, 372 

Rivers, Obstructions in, 385 

Rivers, Surface and Bottom Velocity of, 385 

Riveter Supporting ('ran,-. 216 

Riveting a Cunard Linei at Clydebank, 228 

Riveting Machine and Bridge Building 2 6 44 

Road Bridge at Dalginross Comrie, 130 
,; " ; "< Bridges, Genera] Specification fot 143 
Road Bridges, Index to Specification for, 126 
R° u « Bearings, Calculations for, 375 
K " 11 " LlM Bridge, Barrow-in-Furness, L38 
Roller L,tt l: "' 1 '-' over Si„ r . Ireland, L6, 17. 64, 

Roller Lift Bridge (Swale), 2, 13, 17. 47. 64 
Roller Path foi Swing Bridge, 7, 8 

k " 11 "' l:,n - '"' '• ■ «■■ «^ti Manchester Ship 

Canal. 135 ' 

Roller Track for 150-Ton Crane, 264 
Rolling Friction, Experiments on, 379 

Roof Columns, Diagrams and Formulas for Calcu- 
lating, :;:{7 

Roof Drainage, :;:*» 
Rooi Sulfa,, !S , Wind Pressure 
Formula), 390 

Roof and Workshops, l'l', 139-208 
Roofs, Design of, 139 
Rowan's Workshops, l'4. 14:;. L90 
Rusting of Iron in Water. 410 



•ii (Duchemin'fi 



AJ 



Sawmills, Clydebank, 14«t 
Schaffhausen Timber Bridge, 59 
Scheme oi Dalmarnock Works, 32, 33 56 

Scherzer Rolloi Lifl Bridge, Barrow-in-Furness, 

138 

Scherzer RoUer Lift Bridge, Suir, Ireland, 16, 18, 
47. 64, L08 

Scherzer Roller Lift Bridge, Swale, 2, 13, 17.47. 
64, 102 

Scotstoun Vai-,1 Workshops, Farrow's, 182 
Scott's Shipbuilding and Engineering Workshops, 
24, 145, L76 

Sections. Vat-inns. Fwn.u,!;,. f,„- Md.K-nt ..f I,,,-,, 
Radius of Gyration, &c., 345 

Shafts for Bridge Pier Foundations, 275. See I 

J'.'. 47. 7". 98 



^ 





















,ui' • 






- 



INDEX. 



471 



Shaft*, etc., Fmmnhe for Moment of Inertia, 

Radius of Gyration, etc., of, 345, 362 
Shafts, Mine, Compressed-Air Plant for Sinking, 

Shearing Forces in Beams, Formula and Diagrams 

for, 281 
Shearing Strength of Mortar Joint, 404 
sheetB , Corrugated, Calculations for,: 373 
Shipbuilding Berth at Beardmore s Works, L50 

SMphuilding Berth, Harland and Wolffs, 1»* 
ShipbuUding Berths, Electric Derricks for, 272 

Shipyard Cranes, 220 

Sinking Caissons for Pier Foundations, L7, 46, M. 

Sinking Foundations a1 Forth Bridge, ?0, ,1. 

Tay Bridge, 82, 396 
Skew Bridge Enfluence Lines, Calculation of, -._., 
Sliding Friction, Experiments on, 379'' 

Smiths I). m-U « ...ninny's Sheds, L4B 
S-Eastern and Chatham BaUway Bridge, Swale, 

2, 13, 17. 47. 64, L02 
Southwark Cast-iron Bridge, 61 
Specmcation, General, for Road Bndges ■ «;; 

Specification for L50-Ton Hammer-Head Elect™ 

Crane, 270 
Specification for Railwaj Bridges, 428 
Specifications for Pumps, 214 
Specification, General, for Structural Steelwork 

for Travelling Cranes, 422 
Specification for Structural Portion of Heavy Canti- 

lever Cranes, 419 
Specification for Workshops, 152 
Specifications for Bridge Superstructures, 429 
Sheer's Steel Works Building, 2«S, 45,200 
Stability and Flotation of Rectangular Pontoons, 
4» >o 

Stack, Chimney, Guinness s, 2()S 
Stamping Press, Hydraulic, 250, 252. See 45 
Station, Electric Power, 26, L42, 1*4. 204 
Station Roof, Railway, L42, 144 

Steel Bridges, 61 

Steel Compan) of Scotland, Boilers, 3 
Steel Company of Scotland, Workshops. L45 
steelworks. Spencer's, Newburn, 26, 14... Ml 
Stewart and Lloyds' Workshops. 24, 14... i«-»" 

StiflEeners, 372 

Stun,-. Properties of , 114. Weights, 416 

stun,, Records at Forth Bridge, 388 

Strength of Brickwork. 404 

Strength of Cemeni and Concrete, 407 

Strength of Columns, Ultimate, 340 

Strength of Flat Plates, Calculations for, 373 



^t rength of Rings, Calculations for. 372 
Strength, Shearing, of Mortar Joint, 404 
Stresses, Combined, of Beams, etc., Calculations 

for, 371 
Stresses on Timber, 402 

Stressing Gear for Temporary Tics in Bridge 

Building, 102 

Structures. Framed. Calculations for Deflection of, 

366 
Subaqueous Foundations for Bridge Piers, IT. 46, 

82, 98, 396 

Success. Foundations of. 1. 59, 139, 211 

Sudan Railway Bridges, 126 
Sunderland, Bridge over Wear, 14. 17. 64, 97 
Superimposed Loads on Floors of Bridges, 412 
Surface Friction in Foundations, 399 
Suspension Bridges, 61 

Swale Bridge (Schcr/.er Holler Lift). 2, 13, 17. 4,. 

Swing Bridge over Avon, Bristol, Foundations, 397 
Swing Bridge over Barrow River, Ireland, 16,64, 

Swing Bridge over Manchester Ship Canal, 8, 10, 

64, 136 
Swing Bridge for Railway over Canal, 1W 
KS B*U Specification for Railway Bridges, 

441 

Swing Span at Nile Bridge, Cairo, 94, 96 



Tannery Buildings, Canterbury, 2... 145 
Tsy Bridge, 2, 8, 64, 79, 396 
Telford's Bridge, Menai Straite, 61 
Temperature Effect on Continuous Girders,! 

Temperature Effects, 391 
Template Work, 36, 37 

Temporary ftes, &c. J Bending 

Tension or Comp^^^ for ^ 

an d (Combined Stress ^ . 

Tensi0 n Gear for Temporary Ties m Briog 

Tests of Brick Piers, 406 
Tests of Timber, 401 

T— Bridge «ver tW A.I.U, » 

Theorem of Three Momente, 303 

Three-Moment Theorem, 302 

Timber Bridges, 59 
Timber Piles, Loads on, 400 

Timber Teste, m of m 

Timber, Wei andPry, B 

Timber, Wo^n,, Stresses-.,^ ^ 

Timbers, Properties o^ 414. 



/±. 



J>** 







472 



INDEX. 









Tower Bridge, London. 2. 10, 11, 64, 87, 396 
Tower, Campanile, Cremona, Foundations, :'>!>7 
Track, Roller, for 150-Ton Cram-. 264 
Track for Swing Bridge. Roller, L35 
Traffic at L.»ndon Tower Bridge, 92 
Train Loads, Moving, .".Hi 
Tranmere Workshops, 24. 14... L61 
Travelling Cranes; Approximate Weights, 38J 
Travelling Cranes, Standard Specification for Struc- 
tural Steelwork, 422 

Trestle Piers, Specification for Railway Bridges 
439 * 

Tubular Bridge, Britannia, 62 
Turbine Erecting Shop, Clydebank, 147 
Turbine Workshops, Parsons', 186 
Turntables, Pressure on Discs of , :;77 

Ultimate Strength of Columns, 340 
Union Bridge, Tweed. Berwick. «il 

Valves and Fittings, Hydraulic, 247 

Viadud Approach to Forth Bridge, 76, 77 

Viaduct over Barrow River, Ireland, 16, 64, 108 

Viaduct at Bothwell, 4. :,. 64 

Viaduct, Longest (Tay), 2, 8, 64, 7". 396 

Viaduct over Suir River, Ireland, lfi. 18,64, 108 

Viaduct over Walney Channel. Barrow-in-Furness 
138 

Vickers' Workshops, l'4. 145, 158 



UK' 



Wallsend Slipway Company's 150-Ton Cn 

Foundations. 397 

Walkend Slipway and Engineering Workshops 

24. 145, 172 ' 

Walls, Loads on Girders in, :!80 



Walney Channel Viaduct. Barrow-in-Furness, 138 
Warehouse Foundations. Great Central Railway 

Maryiebone, 397 
Water Pressure, Calculations for, 385 

Waverley Station, Edinburgh, North Bridge ov. 
123 

Wear Bridge, Sunderland, 14. 17. 64, 97 

Wear Cast -Iron Bridge. <il 

Web Flat. -s. Calculations for, 372 

H eight of Kentiledge for ( Jounterweight, 411 
Weight of Timber, Wet and Dry. 4<>o 
Weights of Material, 4 Hi 
Weights of Travelling Cranes, 381 
Weiis Workshops, Catheart, 145, L94 
Westminster Bridge Foundations, ."-"7 
Wheel (Crane) Loads on Top Flanges 

Girders, Distribution of, 384' 
Widening of B&ckfriars Bridge, London, i:;,; v 412 
^ illiamsburg Bridge, 62 
Williamson's Tannery, Canterbury, 14:. 
Wind Pressures, 386 

Wind Resistance of Various Surfaces, 389 

Withdrawing Machinery, Gas Retort, 237 

Wittingen Timber Bridge, 59 

Wood. Properties of, 414 : Weights, 416 

W ooden Bridges, 59 

Workmen, Company's, 2!» 

Workshop Buildings, General Specification for, 452 

Workshop Tools, Experience in, 211 

Workshops Built by Sir W. Arrol and Co., L42-146 

W orkshops, Designs of. 139 

Workshops and Boot's, 22, L39-208 



"t Gantry 



Y. 



arrows Workshops at Poplar and Scots,,,,,,, >4 
145. 17S 




,,K,NTK " AT ™>- B7 ^^^r^i^^ 



1 i-v, Strand, Londo.v, W.c. 



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